To stop pepole hijacking other topics, I thought I would start a new thread here for people to discuss the caves of the Blackmoor area (Upper Flood Swallet, Waterwheel Swallet, Grebe Swallet, Blackmoor Swallet, Blackmoor Shaft etc).
To begin with, here is MCG's survey (1976) of the area:

The caves are shown with the names used by MCG at that time:
Bank Subsidence, Altitude 237.5m = point upstream of UFS where stream is known to sink
Upper Flood Swallet, Alt 237.6m
Middle Flood Swalet, Alt 234.5m = Waterwheel Swallet
Lower Swallets = points where water seen to sink since 1968 flood, now lost?
Grebe Swallet, Alt ???m. Has also been known as Lower Flood Swallet but see above
Blackmoor Swallet, Alt ???m = MCG dig in 1950's/1960's. Inspected May 2007, no longer accessible
Shaft, Alt 240.5m = Blackmoor Shaft = Stainsby's Shaft