I saw it last Saturday and I agree - great fun. Not a great play, but a good one and a brilliant production. I'd never been to Studio 2 before but I really liked it - the only times I couldn't see everything on stage was when Nigel Harman's bum was obscuring my view.

Sad to see a few empty seats, though.
I went mainly to see Nigel (not just his bum) and while he didn't disappoint at all, his character was probably the least well-written of the three and it was the other two performances that really impressed me: Robert Daws was perfect and Steven Webb found an incredible amount in what could easily be a totally thankless role.
Sure, the plot is rather contrived in places and act one ends with the most shameless "there's no way you're going to leave at the interval" cliffhanger I've seen in a long time (not that there's any way I would have done), but the dialogue is great, and it was nice to see a "gay play" (a) that didn't leave me thoroughly depressed, and (b) where the characters' sexuality was not actually the focus - while it wouldn't have anything like the same impact, the story would still technically make sense if the characters were straight.