I did my ppl there over the summers of 2003/4 and can back up what is said about the aircraft; old-ish warriors, but beautifully maintained. The instruction is terrific, no bored hour-builders. Mostly career instructors and an alarming number of ex-concorde pilots - who must find the change of pace quite dizzying.
The planes do get booked up in advance but once you have your ppl you can usually organise something at reasonably short notice. If I had a criticism, there isn't the same social scene that you perhaps get somewhere like White Waltham, but given that I live in central London, not sure how much of the social scene I'd see anyhow.
Dick Thurbin would be my instructor of choice - gave me confidence to do something I never thought possible.
Good luck!