About 43 mins:
https://www.bbc.co.uk/iplayer/episode/m000n81b/countryfile-south-devon

Chris Smallbones must be Nigel Smallbones son! Nigel was the ranger when we were exploring and surveying the systems on Berry Head back in the 80's that led to the quarry being protected.

Not quite bats, but I recently picked up the quaternary research association's Devon & East Cornwall field guide 1996,  and it has almost 50 pages on underground research at Berry Head, Kent's cavern & Torbryan caves.(The caving library don't appear to have a copy, & it doesn't seem to be easily available either)