In reply to sithornhill:
wall is part of the Reebok Sports Centre - above Waitrose in Canada Place.
http://www.reeboksportsclublondon.com/home/index.php
As far as I know, you need to join the entire gym to play on the wall - and it's about £80 a month. For that you get free classes, a huge gym and good facilities. As for the wall - it's 13m and six routes wide. Autobelays. Never seen anyone top-roping or leading, but it is all bolted for that purpose.
Is it any good? Depends what you're after -
if you're after a wide variety of routes, great atmosphere, choice of bouldering, difficulties, textures ... don't go anywhere near it.
if you're after a wall with guaranteed no-queues, no need for partner, and some hard climbing if you're up to it (see above!) ... it's probably the best venue in London.