I'll reiterate the Fairlop Waters envy! How cool to have a place like that within easy walking distance of a Tube stop. I'll definitely have to give it a go the next time I'm in London.

The problem I've been having with climbing outside is transportation. While my area isn't exactly overrun with places to climb outdoors, there are a few, but they're all nearly impossible to get to without a car. Most of them are also not bouldering spots, so not only does one need a car, but also people and equipment and all that. And since most of the people I climb with are carless, urban, indoor climbers, it makes things a bit difficult. So perhaps Greater London is lacking natural rock, but at least you can get to what you've got relatively easily and have the opportunity to climb alone and with minimal equipment, if that's your preferred way to do it.