I'm sure exactly where Sawmill used to be, however devils silt & devils hole (which I believe were near a dig to regain sawmill) no longer exist. About 12 years ago (+/- a bit) I found the entrances but never got round to going back to look at them. Approx. 5 years ago I eventually did 'go back to them' and found the face of rock they used to be in had been replaced by a large hole. If Sawmill was somewhere underneath these, then its long gone. There was a phase a few years ago of bits of Portland stal getting sold on ebay by quarry men - maybe this was linked with 're-entering' sawmill?