In reply to BethanWhite:
Hi Bethan,
Jamie's timings above look pretty sound to me, I would also add Swanage (~3 hours) for Sea cliffs.
The thread Jamie linked has good info about the three local clubs that I am aware of. There is also a "open session" on thurdays where the wall provide gear and the instructors are around to help (for a slightly higher price). Although it is mainly aimed at novices it could be another way of meeting people.
Other walls nearby are:
Reading (large ropes area and some good bouldering)
Milton Keynes - Big Rock (Not as much roped stuff but a nice bouldering area with circuits)
Warwick Uni - Bear Rock (Very big bendcrete overhang)
The local gear shops are Go Outdoors (near the Redbridge park and ride), Cotswold at Bicester and Outdoor traders in Abingdon.