Fascinating pics, Graham: thank you for uploading them.
It's quite amazing how much the site has deteriorated since then. The loss of roofing slates will have exposed the walls to the elements and it can get rather unpleasant up there in the winter, to say the least. Do you know whether the slates were recovered by the owners or whether they just disappeared?
Presumably the drive shaft tunnels are no longer accessible?
Hello again darkness, my old friend...