Hi Brian,
I got my PADI a few years back out in the Maldives. My god, but sea there is something else. Anyway, I'm type 1 and it hasn't stopped me from diving at all. If you're type 2 it should be even less of a problem since hypo's are less of an issue for you guys.
I always tell the dive guides beforehand, test my bg before diving, and everything's fine and dandy.
I've never dived in UK waters, for all the obvious reasons, although the west coast of Scotland is apparently not too bad/cold/polluted. Reckon I can wait until Greece this summer!
All the best,
fergus