The British Caving Association

Both are around the 70 to 80 Km mark.

In Britain: Ogof Draenen
In England: Lancaster - Easegill - Pipikin - Lost Johns

But then the Easegill System oftem tops the list for Britain as well when cavers go and survey more passge until they do the same in Wales!

I can't see that there could be a problem with this - the geocache listing clearly states the difficulty and the danger in entering the cave - so it's unlikely that people who can't deal with caves will go for it. it's not like people are going to risk their bits for this cache without having done ...