REG — Senior PLC — Holding(s) in Company

For best results when printing this announcement, please click on link below: RNS Number: 6246V Senior PLC 21 September 2026 TR-1: Standard form for notification of major holdings 1. Issuer Details ISIN GB0007958233 Issuer Name SENIOR PLC UK or Non-UK Issuer UK 2. Reason for Notification An acquisition or disposal of voting rights 3. Details of person subject to the notification obligation Name BlackRock, Inc. City of registered office (if applicable) Wilmington Country of registered office (if applicable) USA 4. Details of the shareholder Full name of shareholder(s) if different from the person(s) subject to the notification obligation, above City of registered office (if applicable) Country of registered office (if applicable) 5. Date on which the threshold was crossed or reached 18-Sep-2026 6. Date on which Issuer notified 21-Sep-2026 7. Total positions of person(s) subject to the notification obligation. % of voting rights attached to shares (total of 8.A) % of voting rights through financial instruments (total of 8.B 1 + 8.B 2) Total of both in % (8.A + 8.B) Total.