I started and completed my PPL at Synergy this year who are based at Fairoaks, just off J12 Chertsey/Woking junction of the M25. They do trial lessons of varying lengths. I live in SW3 and found it convenient enough for me, although I am semi retired so I aimed for around four afternoons/week midweek. The trip is 40 mins on a good day, but I usually factor in an hour.
Www.flysynergy.com FWIW. The benefit is that there are three options to get there from West London if traffic is playing up, which it usually is.
Cheers, Howard