Interesting.
Water is a long way down up there. 100m+
Most of the shafts are vertical to adit level and any workings above adit are also vertical. I've been up there and looked at pretty much everything which is open and everything, apart from the incline shaft near the short stack is 300ft deep. My money is it being one of the two shafts adjoining the golf place which I haven't looked at.
There is a shallow(er) adit which comes in from Peevor but is blocked shortly GND side of the road. Perhaps this shaft drops onto the other side of the collapse. If it was the case, it would be interesting to look at, as it would appear to be on a different set of workings than the main deep stuff.