In reply to DaveHK:
> They're very different things. The SMC is a big club, the BMC is a governing body.
I consider the BMC to be a representative body, not a governing body, for my climbing activities.
Many of the issues over the last few years have come about because some people feel that they are not being represented.
They also provide me with Third party liability.
They also facilitate my clubs via insurance.
The OP, has not said what they want from the BMC or SMC, as it's a first posting, I will reserve my judgement on their motives for posting, but without knowing what the OP wants, it's impossible to advise.
As a walker the Ramblers do a good job for me.