In reply to jaxxman:
Works is a no-brainer really, but that isn't to say the others aren't worth checking out - they are.
The Foundry has a bouldering scene of its own.
The Matrix is a bit limited, but its nice enough and its cheap.
(Also consistently much warmer than the Works which isn't a good thing most of the time, but it's been a godsend a couple of times this winter when the Works was just *too* cold.