Acquisition and Scheme Timetable Update

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY, IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF SUCH JURISDICTION

FOR IMMEDIATE RELEASE

18 December 2025

RECOMMENDED CASH ACQUISITION

of

DELTIC ENERGY PLC ("Deltic")

by

ROCKROSE ENERGY LIMITED ("Viaro Bidco")

(A WHOLLY-OWNED SUBSIDIARY OF VIARO ENERGY LIMITED)

to be effected by means of a scheme of arrangement under

Part 26 of the Companies Act 2006

Acquisition and Scheme Timetable Update

On 30 June 2025, the boards of Viaro Bidco and Deltic announced that they had reached agreement on the terms of a recommended cash offer for the entire issued and to be issued ordinary share capital of Deltic (the "Acquisition"), to be implemented by way of a Court-sanctioned scheme of arrangement under Part 26 of the Companies Act 2006 (the "Scheme") which was approved by Deltic shareholders on 28 August 2025.

Completion of the Acquisition remains subject to outstanding conditions, which include, inter alia, the consent of the North Sea Transition Authority (the "NSTA") to a change in control of the North Sea exploration licences held by Deltic.  The NSTA is the UK regulator focused, among other areas, on oil and gas exploration and production activities in the UK's North Sea.

Deltic has been informed that Viaro Bidco has requested, and the NSTA has agreed to, an extension to the date by which it requires further representations from Viaro Bidco in order to reach a definitive conclusion in relation to concerns it has which will affect whether it will grant the proposed change of control of the licences held by Deltic.  The NSTA has now agreed that this information should be provided to it by 30 January 2026.

A further announcement will be made in due course.

Capitalised terms used in this announcement (the "Announcement") shall, unless otherwise defined, have the same meanings as set out in the Scheme Document published on 25 July 2025. All references to times in this Announcement are to London, United Kingdom times unless stated otherwise.

**ENDS**

Enquiries:

Important notices about financial advisers

H & P Advisory Limited, trading as Hannam & Partners, which is authorised and regulated by the FCA in the United Kingdom, is acting exclusively for Viaro Bidco and no one else in connection with the matters described in this Announcement and will not be responsible to anyone other than Viaro Bidco for providing the protections afforded to clients of Hannam & Partners nor for providing advice in relation to the subject matter of this announcement. Neither Hannam & Partners nor any of its affiliates owes or accepts any duty, liability or responsibility whatsoever (whether direct or indirect, whether in contract, in tort, under statute or otherwise) to any person who is not a client of Hannam & Partners in connection with this announcement, any statement contained herein or otherwise.

Allenby Capital Limited, which is authorised and regulated by the FCA in the United Kingdom, is acting as financial adviser to Deltic and no one else in connection with the matters described in this Announcement and will not be responsible to anyone other than Deltic for providing the protections afforded to clients of Allenby Capital nor for providing advice in connection with the matters referred to herein. Neither Allenby Capital nor any of its subsidiaries, branches or affiliates owes or accepts any duty, liability or responsibility whatsoever (whether direct or indirect, whether in contract, in tort, under statute or otherwise) to any person who is not a client of Allenby Capital in connection with this announcement, any statement contained herein, any offer or otherwise.

Further Information

This Announcement is for information purposes only and is not intended to and does not constitute, or form part of, any offer to sell or an invitation to purchase any securities; a solicitation of an offer to buy, otherwise acquire, subscribe for, sell or otherwise dispose of any securities pursuant to the Acquisition or otherwise; or the solicitation of any vote or approval in any jurisdiction pursuant to the Acquisition or otherwise nor shall there be any purchase, sale, issuance or exchange of securities or such solicitation in any jurisdiction in which such offer, solicitation, sale issuance or exchange is unlawful.

The statements contained in this Announcement are made as at the date of this Announcement, unless some other time is specified in relation to them, and publication of this Announcement shall not give rise to any implication that there has been no change in the facts set forth in this Announcement since such date.

This Announcement does not constitute a prospectus or prospectus equivalent document.

Disclosure requirements of the Takeover Code

Under Rule 8.3(a) of the Takeover Code, any person who is interested in 1 per cent. or more of any class of relevant securities of an offeree company or of any securities exchange offeror (being any offeror other than an offeror in respect of which it has been announced that its offer is, or is likely to be, solely in cash) must make an Opening Position Disclosure following the commencement of the Offer Period and, if later, following the announcement in which any securities exchange offeror is first identified. An Opening Position Disclosure must contain details of the person's interests and short positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree company and (ii) any securities exchange offeror(s). An Opening Position Disclosure by a person to whom Rule 8.3(a) applies must be made by no later than 3.30 pm (London time) on the 10th business day following the commencement of the Offer Period and, if appropriate, by no later than 3.30 pm (London time) on the 10th business day following the announcement in which any securities exchange offeror is first identified. Relevant persons who deal in the relevant securities of the offeree company or of a securities exchange offeror prior to the deadline for making an Opening Position Disclosure must instead make a Dealing Disclosure.

Under Rule 8.3(b) of the Takeover Code, any person who is, or becomes, interested in 1 per cent. or more of any class of relevant securities of the offeree company or of any securities exchange offeror must make a Dealing Disclosure if the person deals in any relevant securities of the offeree company or of any securities exchange offeror. A Dealing Disclosure must contain details of the dealing concerned and of the person's interests and short positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree company and (ii) any securities exchange offeror(s), save to the extent that these details have previously been disclosed under Rule 8. A Dealing Disclosure by a person to whom Rule 8.3(b) applies must be made by no later than 3.30 pm (London time) on the business day following the date of the relevant dealing. If two or more persons act together pursuant to an agreement or understanding, whether formal or informal, to acquire or control an interest in relevant securities of an offeree company or a securities exchange offeror, they will be deemed to be a single person for the purpose of Rule 8.3.

Opening Position Disclosures must also be made by the offeree company and by any offeror and Dealing Disclosures must also be made by the offeree company, by any offeror and by any persons acting in concert with any of them (see Rules 8.1, 8.2 and 8.4).

Details of the offeree and offeror companies in respect of whose relevant securities Opening Position Disclosures and Dealing Disclosures must be made can be found in the Disclosure Table on the Panel's website at www.thetakeoverpanel.org.uk, including details of the number of relevant securities in issue, when the Offer Period commenced and when any offeror was first identified. You should contact the Panel's Market Surveillance Unit on +44 (0)20 7638 0129 if you are in any doubt as to whether you are required to make an Opening Position Disclosure or a Dealing Disclosure.

Electronic Communications

Please be aware that addresses, electronic addresses and certain other information provided by Deltic Shareholders, persons with information rights and other relevant persons for the receipt of communications from Deltic may be provided to Viaro Bidco during the Offer Period as required under Section 4 of Appendix 4 to the Takeover Code to comply with Rule 2.11(c) of the Takeover Code.

Overseas jurisdictions

The release, publication or distribution of this Announcement in jurisdictions other than the United Kingdom, and the availability of the Acquisition to Deltic Shareholders who are not resident in the United Kingdom, may be restricted by the laws of those jurisdictions and therefore persons into whose possession this Announcement comes should inform themselves about and observe such restrictions. In particular, the ability of persons who are not resident in the United Kingdom to vote their Deltic Shares with respect to the Scheme at the Court Meeting, or to execute and deliver forms of proxy appointing another to vote at the Court Meeting on their behalf, may be affected by the laws of the relevant jurisdictions in which they are located. Further details in relation to Overseas Shareholders will be contained in the Scheme Document (or, if the Acquisition is implemented by way of a Takeover Offer, the offer document). Any failure to comply with any such restrictions may constitute a violation of the securities laws of any such jurisdiction. To the fullest extent permitted by applicable law, the companies and persons involved in the Acquisition disclaim any responsibility or liability for the violation of such restrictions by any person.

Unless otherwise determined by Viaro Bidco or required by the Takeover Code, and permitted by applicable law and regulation, the Acquisition will not be made available, directly or indirectly, in, into or from a Restricted Jurisdiction. Accordingly, copies of this Announcement and all documents relating to the Acquisition are not being, and must not be, directly or indirectly, mailed or otherwise forwarded, distributed or sent in, into or from a Restricted Jurisdiction, and persons receiving this Announcement and all documents relating to the Acquisition (including custodians, nominees and trustees) must not mail or otherwise distribute or send them in, into or from such Restricted Jurisdiction. If the Acquisition is implemented by way of Takeover Offer (unless otherwise permitted by applicable law or regulation), the Takeover Offer may not be made, directly or indirectly, in or into, or by use of mails or any other means or instrumentality (including, without limitation, facsimile, e-mail or other electronic transmission, telex or telephone) of interstate or foreign commerce of, or any facility of a national, state or other securities exchange of any Restricted Jurisdiction and the Takeover Offer will not be capable of acceptance by any such use, means, instrumentality or facilities or from within any Restricted Jurisdiction.

This Announcement has been prepared in connection with proposals in relation to a scheme of arrangement pursuant to and for the purpose of complying with English law and the Takeover Code and information disclosed may not be the same as that which would have been disclosed if this Announcement had been prepared in accordance with the laws of jurisdictions outside the United Kingdom. Nothing in this Announcement should be relied on for any other purpose.

The Acquisition shall be subject to the applicable requirements of the Takeover Code, the Panel, the London Stock Exchange, the FCA and the AIM Rules.

Additional information for U.S. investors

The Acquisition relates to the shares of an English company and is being made by means of a scheme of arrangement provided for under English company law. A transaction effected by means of a scheme of arrangement is not subject to the tender offer or proxy solicitation rules under the US Exchange Act. Accordingly, the Acquisition is subject to the disclosure requirements and practices applicable in the United Kingdom to schemes of arrangement which differ from the disclosure requirements of the US tender offer and proxy solicitation rules.

If, in the future, Viaro Bidco exercises its right to implement the Acquisition by way of a Takeover Offer, which is to be made into the US, such Takeover Offer will be made in compliance with the applicable US laws and regulations, including Section 14(e) and Regulation 14E under the US Exchange Act. Such a Takeover Offer would be made in the US by Viaro Bidco and no one else.

In accordance with normal United Kingdom practice and pursuant to Rule 14e-5(b) of the U.S. Exchange Act, Viaro Bidco, its affiliates, their advisers and the nominees or brokers (acting as agents) may make certain purchases of, or arrangements to purchase, shares in Deltic outside the Acquisition, such as in open market purchases or privately negotiated purchases, during the period in which the Acquisition remains open for acceptance. If such purchases or arrangements to purchase were to be made, they would comply with applicable law, including UK laws and the US Exchange Act. Any information about such purchases or arrangements to purchase shall be disclosed as required under UK laws and will be available to all investors (including US investors) via the Regulatory Information Service and shall be available on the London Stock Exchange website at www.londonstockexchange.com. To the extent that such information is required to be publicly disclosed in the UK in accordance with applicable regulatory requirements, this information will, as applicable, also be publicly disclosed in the United States.

It may be difficult for US holders of Deltic Shares to enforce their rights and any claim arising out of the US federal securities laws in connection with the Acquisition, since Viaro Bidco and Deltic are located in non-US jurisdictions, and some or all of their officers and directors may be residents of non-US jurisdictions. US holders of Deltic Shares may not be able to sue a non-US company or its officers or directors in a non-US court for violations of the US securities laws. Further, it may be difficult to compel a non-US company and its affiliates to subject themselves to a US court's judgement.

Neither the Acquisition nor this Announcement have been approved or disapproved by the US Securities and Exchange Commission, any state securities commission in the United States or any other US regulatory authority, nor have such authorities approved or disapproved or passed judgement upon the fairness or the merits of the Acquisition, or determined if the information contained in this Announcement is adequate, accurate or complete. Any representation to the contrary is a criminal offence in the United States.

The receipt of cash pursuant to the Acquisition by a US holder as consideration for the transfer of its Deltic Shares pursuant to the Acquisition will likely be a taxable transaction for US federal income tax purposes and under applicable US state and local, as well as foreign and other, tax laws. Each US holder of Deltic Shares is urged to consult their independent legal, tax and financial advisers regarding the tax consequences of the Acquisition applicable to them, including under applicable US state and local, as well as overseas and other, tax laws.

Forward-looking statements

This Announcement (including information incorporated by reference in this announcement), oral statements made regarding the Acquisition, and other information published by Viaro Bidco or Deltic may contain statements about Viaro Bidco and Deltic that are or may be deemed to be forward-looking statements. All statements other than statements of historical facts included in this Announcement may be forward-looking statements. Without limitation, any statements preceded or followed by or that include the words "targets", "plans", "believes", "expects", "aims", "intends", "will", "may", "shall", "should", "anticipates", "estimates", "projects", "is subject to", "budget", "scheduled", "forecast" or words or terms of similar substance or the negative thereof, are forward-looking statements. Forward-looking statements include statements relating to the following: (i) future capital expenditures, expenses, revenues, earnings, synergies, economic performance, indebtedness, financial condition, dividend policy, losses and future prospects; (ii) business and management strategies and the expansion and growth of Viaro Bidco's or Deltic's operations and potential synergies resulting from the Acquisition; and (iii) the effects of government regulation on Viaro Bidco's or Deltic's business.

Such forward-looking statements are prospective in nature and are not based on historical facts, but rather on current expectations and projections of the management of Viaro Bidco and Deltic about future events, and are therefore subject to risks and uncertainties that could significantly affect expected results and are based on certain key assumptions. Many factors could cause actual results to differ materially from those projected or implied in any forward-looking statements, including: changes in the global, political, social, economic, business, competitive, market and regulatory forces, future exchange and interest rates, changes in tax rates, future business combinations or disposals, changes in the behaviour of market participants, the speculative nature of oil and gas exploration, fluctuations in demand and pricing in the oil and gas exploration industry and risks and hazards associated with the business of oil and gas exploration. Other unknown or unpredictable factors could cause actual results to differ materially from those in the forward-looking statements. Such forward-looking statements should therefore be construed in light of such factors. Neither Viaro Bidco nor Deltic, nor any of their respective associates or directors, officers or advisers, provides any representation, assurance or guarantee that the occurrence of the events expressed or implied in any forward-looking statements in this Announcement will actually occur. Due to such uncertainties and risks, readers are cautioned not to place undue reliance on such forward-looking statements, which speak only as of the date hereof. All subsequent oral or written forward-looking statements attributable to any member of the Viaro Group or the Deltic Group, or any of their respective associates, directors, officers, employees or advisers, are expressly qualified in their entirety by the cautionary statement above.

Viaro Bidco and Deltic expressly disclaim any obligation to update any forward-looking or other statements contained herein, except as required by applicable law or by the rules of any competent regulatory authority, whether as a result of new information, future events or otherwise.

Publication on a website

A copy of this Announcement will be available, free of charge, subject to certain restrictions relating to persons resident in Restricted Jurisdictions, on Viaro Bidco's website at https://viaro.co.uk/disclaimer/ and Deltic's website at https://delticenergy.com/disclaimer/ by no later than 12.00 noon (London Time) on the Business Day following the publication of this Announcement.

General

If you are in any doubt about the contents of this Announcement or the action you should take, you are recommended to seek your own independent financial advice immediately from your stockbroker, bank manager, solicitor or independent financial adviser duly authorised under FSMA if you are resident in the United Kingdom or, if not, from another appropriately authorised independent financial adviser.