In reply to Plug81:
> Has anyone been to Fairlop Waters? Is it any good?
It's OK, and a lot better than not climbing.
> Is it worth the trek over from South London by train and tube?
If you have the time and can't get to real rock, yes. I've only gone by car, and that's a slog. North Circular on a weekend can be grim.
> Do you need a bouldering mat?
Wouldn't hurt, but most landings are flat gravel.
> Is it free?
Yes.
> Does it get busy?
I've been twice and I was pretty much the only climber there.