Return the passport to the issuing PIO within 30 days
so they can invalidate it and update records. You may be able to request
it back after invalidation for sentimental reasons. [gov.uk]
To change or update your horses on membership or insurance policies, please follow the below link to access your account: https://harryhallinsurance.com/#/pages/login Click the 'manage horse' tab and add or change your horse then click the save ...
Before buying: match horse to passport (description, microchip) and ensure the seller hands you the passport at sale. [gov.uk] Within 30 days of purchase: contact the issuing PIO on the passport; submit their change‑of‑ownership form, passport, and ...
If the horse will remain in the UK more than 90 days, you must register the foreign passport with a UK PIO within 30 days of arrival. Follow the import guidance and keep the passport with the horse at all times. [gov.uk] Regards. HH
Enforcement is by local authorities/Trading Standards. Sanctions can include fixed penalty notices and fines; multiple official and PIO sources warn of penalties for non‑compliance (up to £5,000 in some guidance). Regards. HH.
Apply for a duplicate/replacement from the original PIO (or another appropriate PIO if the original is unknown). Duplicate/replacement passports permanently exclude the horse from the human food chain. [gov.uk] Regards. HH.