Thanks for the replies so far, I'll try writing to the DGAC and see what they say.
Re. NPPL vs. PPL, I had a PPL(A) which had lapsed for 6 years, and when I came to renew it I found that I could either fly ratty old PA-28s at Blackbushe for about £120/hr, for the PPL(A) renewal, or a brand new Rotax Super Falke at Lasham for £60/hr. I did my renewal (to NPPL-SLMG) on the Falke and then a conversion check ride in my RV-4 to get the -SEP rating on the licence. So much cheaper, and I didn't need to pay a CAA doctor for the Class 2, although I may have to in order to fly in France, we will see.
NPPL is a great thing, long may it continue!
Cheers, OG