I thought the idea of a wetsuit is that it traps a thin layer of water next to the skin which is warmed by the body, but as it's not being constantly flushed out and replaced (unless your suit is too loose), there is a warming effect. Not sure of the point of neoprene wellies!
Glad to hear the frog made it out! I was in the other group in the cave today (Slough Mountaineering Group) no less... ( but as mentioned in passing, we live in Lancs and Cumbria!). Thanks to the CPC for use of their ropes too. A great trip..
Re the ladder climb in CTH, when I was in there earlier this year, it was possible to squeeze through underneath the jammed overhanging block where the pitch is described. There was then a short wet sideways crawl. Water levels were fairly low, so may not always be passable, but in those...