"Robin - to the Batcave!"

I'll come clean and confess I'm not actually sure what this is. I think it's a disused lime kiln - there is certainly at least one other in the vicinity (the Trowse / Whitlingham Park area). I've heard the other one mentioned as an occasional breeding spot for bats, so perhaps this one is too - although its location (just off Whitlingham Lane, close to the outdoor ski slope, with the tunnel actually running beneath the road) may not be quiet enough. But what do I know?