Or just get a temporary validation of your FAA Licence.
https://www.caa.co.uk/Commercial-ind...n-UK-airspace/
You must:
- hold a valid Licence/Certificate (that is a licence that is not subject to suspension, limitation or other enforcement action by the issuing authority);
- hold a valid, current rating relevant to the aircraft to be operated, and the privileges to be exercised, demonstrable by reference to appropriate log book and licence evidence;
- hold at least a valid Class 2 Medical issued by the issuing authority;
- hold an “English proficient” endorsement on their ICAO licence, to meet the minimum level 4 proficiency, or have their proficiency confirmed by a UK CAA Approved Language Proficiency Assessment Centre if no such endorsement applies or the candidate wishes to be credited with proficiency levels 5 or 6 (FormCAA5003 applies).
- complete an acclimatisation flight, which is a check flight conducted with a qualified UK instructor. The aim of the flight is to demonstrate that you are safe to fly the aircraft in UK airspace.
Hardly onerous, it's a bit of paperwork and a rental checkout, not much different to the FAA biennial that all FAA certified pilots have to do every 2 years at home.
G