Summer of lots of climbing on a budget?

I have a bunch of time off in Summer and wanted to climb as much as possible. Does anyone have any ideas of a way to be able to climb lots on a very low budget? Bearing in mind I live in London, so there's not so much natural climbing on my doorstep.

Was thinking there may be some kind of working scheme, I could work for a climbing camp for accommodation and use of their facilities? Sort of like WOOFING. Are there even such things as climbing camps?

Any suggestions welcome!