10-11 CHARTERHOUSE SQUARE, LONDON EC1M 6EE

TELEPHONE: +44 (0)20 7549 5700

1 June 2026

NON-EXECUTIVE DIRECTOR BOARD CHANGES

Diploma PLC, the value-add solutions group, is pleased to announce the appointment of Mandy Gradden as an independent non-executive director with effect from 1 June 2026. Mandy will join the Audit Committee and the Nomination Committee.

Mandy has over 20 years' experience as a chief financial officer, most recently at Ascential plc. She has also served as a non-executive director and audit committee chair at SDL plc and Spectris plc. Mandy currently chairs the Listing Authority Advisory Panel of the Financial Conduct Authority.

Mandy has a degree in Business from Aston University and began her career at Price Waterhouse, where she qualified as a chartered accountant.

Geraldine Huse will step down from the Board and the Nomination and Remuneration Committees with effect from 15 July 2026.

David Lowden, Board Chair, commented:

"I am delighted to welcome Mandy to the Board. She brings significant experience as a chief financial officer and audit committee member, along with deep financial and regulatory expertise.

We thank Geraldine for her commitment and valuable contribution to the Board and wish her well for the future."

There is no other information that is required to be disclosed pursuant to UK Listing Rule 6.4.8R.

Anna Lawrence

Group General Counsel & Company Secretary

Diploma PLC

For further information, please contact:

Further information on Diploma PLC can be found at www.diplomaplc.com

LEI: 2138008OGI7VYG8FGR19