If you do a trip here then might the 24th of April be a good time? I am headed down to Wales then anyway to do mine trips around Betws, if I can't make it then oh well!
I have tried using a video camera underwater before on a string and it's very difficult, might have more luck photographing the workings underwater on a long exposure by placing camera on a small tripod in waterproof case and somehow attaching it to the edge, probably have to hold it in place somewhat, then lower some torches. The last time I tried this the case leaked and hence I had to buy a new camera lol.
Willy I think it's always more fun with a boat. In regard to the landowner in all likelyhood not being pleased about the big drop appearing, well I read an article today about some guys who used a petrol pump to drain a mine in a few days, granted the amount of water they had to remove was significantly less, but nevertheless they stayed on site for the entire few days it took them, so I would probably try and do the same, put up signs etc with landowner's permission
jeg elsker Norge, landets dialekter, folk, landskap og naturen!