my god, I've died and gone to heaven ! 2 geo threads !!
Without doubt, in my opinion the best place for a geometry in and around the London area is Wheels in Motion. These people will get the figures within minutes of a degree opposed to 'in the green, yeah its fine' I'd go as far to say they are better than Centre mavity (arguably one of the best places in the country for Porsches and S2000's)
I believe Tony charges in the region of £90 for a geometry check. However you get 2 or 3 adjustments (I can't remember) for free after. Translate that as, he sets the car to stock, you go off and drive it, decide it feels light/not direct enough, too fast turn in etc etc. Thats absolutely superb if you use the car on the track or are a bit enthusiastic on the road.
When my S2000 goes in for a geo they can adjust Caster, Camber and Toe at the front, and Camber and Toe at the back. Not all cars can have this done from the factory, and some will need adjustor plates/other parts fitted to do it.
Call Wheels In Motion, ask for Tony, and say Gareth with the S2000 recommended you... See what he can offer....