Dysinni,
I recently flew in Portugal (in Lisbon though, not in the Algarve) and I found there are quite a few UK registered planes there. According to the instructor I flew with that's because it's cheaper to register in the UK than in Portugal.
So if you get in touch with the club ahead of time you may actually get hold of a G reg craft and avoid having to transfer the license or fly on the left side.
Mak