Hi Paul,
We visited Bwlch-y-Plwm Lead Mine in North Wales earlier in March and there were a number of flooded stopes on Deep Adit (Level 1) and I did post a query on this forum, if they had been dived, but no replies as yet.
Deep Adit is an open, roomy level, ideally situated, just below the same country lane, where you park, a short distance away(Limited parking for 2/3 cars).
Location of first flooded stope is short distance from entrance, along first side passage on right. Others are located further into mine at a main junction(See surveys on this website). Easy to locate. Plenty of room to kit up!
If you do decide to follow this up, then I would certainly be interested in what you find!
By the way, the flooded bottom level in Long Rake, I have seen dry, once, some years ago! Only first section of mine is presently accessible, due to a crawl, being partially blocked with tailings and requiring, a small amount of shuttering. Sadly, mine has seen better days!!!
ATB,
Spires.
PS.
Drop me a pm, for locations of a couple of possible dive sites
in Peak District area.