The SSSI designation is in part a response to the discoveries that were made in Stoney Middleton Dale during the 1970's and 80's. The rest of the designation is ecological. The fact that the caves are protected by law is of benefit to cavers as it means the caves will always be there for cavers today and in the future to enjoy. So what if you have to get permission to put an entrance shaft in? Sarah's Cave and Farnsley Lane Swallets are not protected as they fall outside of the SSSI, and look what has happened to them...
Stoney Middleton SSSIs is not just of importance to cavers. It is of national importance, valuable to geologists, ecologists, archaeologists and recreational users alike. The same rules apply to all users, which thankfully includes developers, utility providers and the quarrying companies... How would you feel if a cave was destroyed? Now put yourself in an ecologist's shoes. They don't want to see habitat destroyed by cavers either.
Permission to undertake surface works has been required since the Dale was notified as a SSSI in 1990. Its only in the last few years that 'reckless' damage to a SSSI has become a criminal offence. In so far as underground digs go, act responsibly and there should not be any problems, after all that's how new discoveries are made... If you are unsure about the law with regards to SSSIs then get in touch with David Webb at the DCA or Jo Poll at Natural England.
Mark C