Recently there was long thread about the BCA. I can now post possible answers to some of the questions, such as "Why is the BCA still raising membership prices when there is a significant amount still left in its coffers?"
"The MNRC can issue permits for CCC controlled caves at 50p for a 14 day temporary permit, and can also issue keys for access to most of the gated caves on Mendip, for a £1 administration fee plus £10 returnable deposit."