there's quite a few come down to BOB rides from SW London, it's easily accessible and the journey shouldn't take much more than 30-40 mins depending on how long it take you to get out of Kingston. I've ridden a few times with THT too and I think their catchment also goes that far as well, so lift sharing could be an easy option too.
Where BOB is also involved with the permit scheme at Swinley via association with the Gorrick people your annual membership gets includes the cost of the annual permit, but that's by a long way not the only area the club rides on, in fact I'd say that most weekend rides are pretty rare to ride in Swinley. there's tonnes of areas around that are 'at least equal'.
There's a Gorrick race at Tunnel Hill in a week's time I think (sunday); both BOB and THT are always well in attendance so come and meet a few, ride the area, see if you like us?