In reply to ianjdodd:
There is a very small and foot smelling place in shoreham (if you're desperate and on a push-bike, otherwise, avoid).
There's K2 in crawley, whose bouldering is pretty small, and whose lead walls are, in my humble opinion, reachy overhung jug haul fests all the way through to the late 6's.
There's craggy in guildford, about 15-20mins further than k2 that is absolutely superb, ludicrous amount of wall space, drytooling wall (pretty basic), and 'ok' bouldering.
Finally, craggy has a second place in Sutton (a tad closer) with excellent bouldering (including some ankle breakingly highballish problems) but no leading. I think they do a lot of compo bouldering here, really interesting problems.
Frankly if you're going for a decent chunk of time, make the effort to go to craggy.