For my money, a proper no holes barred PSE delivered with enthusiasm in London means:
MissKDD
Gabi-Ela
Lia Amelia
Alex (Maxes Angels)
However, they're all over your £200 limit, though 2 or 3 hours works out cheaper with some of them. Others may have suggestions for £200 or less, I'd be interested in those too!
Maggie21 is cheaper and has a good reputation here, but I haven't seen her and I don't know if she does everything that the ones above do..
Sorry, can't post links but they're all reviewed here.