And we find some photo models sans helmets. Peter Glanvill doing all of the work.

PA250001 by Nicholas Chipchase, on Flickr

PA250026 by Nicholas Chipchase, on Flickr

PA250043 by Nicholas Chipchase, on Flickr

PA250056 by Nicholas Chipchase, on Flickr

PA250064 by Nicholas Chipchase, on Flickr

PA250066 by Nicholas Chipchase, on Flickr

PA250069 by Nicholas Chipchase, on Flickr

PA250073 by Nicholas Chipchase, on Flickr

PA250077 by Nicholas Chipchase, on Flickr

PA250088 by Nicholas Chipchase, on Flickr

PA250091 by Nicholas Chipchase, on Flickr

PA250094 by Nicholas Chipchase, on Flickr

PA250098 by Nicholas Chipchase, on Flickr

PA250108 by Nicholas Chipchase, on Flickr

An area cleaned.

PA250116 by Nicholas Chipchase, on Flickr

PA250117 by Nicholas Chipchase, on Flickr

PA250122 by Nicholas Chipchase, on Flickr

PA250126 by Nicholas Chipchase, on Flickr

PA250140 by Nicholas Chipchase, on Flickr

PA250150 by Nicholas Chipchase, on Flickr

PA250152 by Nicholas Chipchase, on Flickr

Another fine UK Caving forum post by Old Ruminator Photo Splodging Services.

PA250074 by Nicholas Chipchase, on Flickr

This one from the vaults. Date 4/12/88. A team shifting a boulder obstructing the free dive from Mystery Pool into the Sump Pool extension first entered in 1967 by PCG.The sump beyond has never been dived to a conclusion.