In reply to AliMackenzie:
> I was just wondering why this isn't happening in Britain?
Dunno, but it's also common in Germany. The Deutsche Alpenverein (DAV) is admittedly a much bigger organisation than the BMC - more like the BMC, YHA, Ramblers Association all rolled into one & then some. But local DAV sections are something like British clubs, and lots of them have their own walls.
Two walls in Munich where I live are owned by the DAV but the Munich DAV is huge - over a hundred thousand members - and the walls are operated by a franchise company as commercial ventures. But lots of smaller towns have bouldering walls owned & run by their local DAV sections.
The only such one I've been to was in north Germany - Bielefeld - and was quite big. They had a routes section that didn't look that great, but a really good bouldering area, v. friendly atmosphere. Payment system was a ticket machine at the entrance with nobody checking if anybody was paying.