In reply to dutybooty:
Probably best to follow the guidance on their website "If you wish to apply and do not know a member to propose your application, we will help you find someone, provided your climbing experience meets the membership requirements." and on the membership form "If you do not know anyone who is eligible to support your application, tick the appropriate box.
We will help by arranging for a member to talk you about your application and, if appropriate, act as your Proposer. The Applications Secretary will contact you to organise this and give you any other advice or help you need."