Booker Aviation at Wycombe Air Park (M40 J4, easy to get to)
Enstone as mentioned
RAF Halton Flying club - not brilliant in the winter however.
RAF Brize Norton Flying Club has a good reputation but is also a very busy operational station.
Several schools at Cranfield, mostly good, about an hour's drive away.
If you're that far down the path, I'd suggest "move into" either WAP or Cranfield for a few days with somebody like Booker or Billins - both have at-least one C172, as well as a good weathproof hard runway and just book an aeroplane and instructor to get you finished off PDQ. I've flown at and with both, and would be happy to recommend both.
Then find where you want to do your post qualification flying - which may or may not be the same place, but certainly need not be.
G