NOTE. Later this year the NPPL will not allow you to fly what used to be EASA aircraft - only non-EASA (oce called Annex 1 aircraft). New terminology is UK Part 21 or Non-UK Part 21 aircraft.
Sadly, the case at the moment. However, I see no valid reason why the DfT/UKCAA shouldn't permit G-reg Part21 aircraft to be flown in UK airspace with a UK-issued licence, including a NPPL, on a medical declaration. Lack of willpower is the only thing holding them back, I believe.
TOO