Information about all cave sites
The Mendip Cave Registry & Archive have a database of all know sites on Mendip. A good place to start is the search facility here.
You can also link the whole database to Google Earth which is a great way of seeing all the sites geographically.
Cave Access Information
Many of the caves on Mendip an be accessed suing a Council of Southern Caving Clubs key. Full access infomation is availble on their access site here
Permits
On Mendip the main permit you need is for Charterhouse Caves which can be obtained from here
Wardens and Leaders
Many BEC members are leaders or wardens for specific caves. A comprehensive list can be found here