With regard to the Devil's Grinding Mill and The Drainpipe, here's an excerpt from my caving log for July 2002:
A motley crew assembled at Fell End early on Saturday afternoon and set off to explore the caves of the Eden gorge at Kirkby Stephen, which sound quite enticing in the guide book, with the promise of fast-flowing streams and a swim out into the gorge; what is not apparent in the guide book is the restricted and somewhat squalid nature of the caves, owing to the accumulation of debris from what must be devastating floods. This consists of rotting vegetation (so deep in places that you actually sink into it); dead animals (presumably sheep, though we didn’t look too closely); old iron, bits of machinery, household utensils, and heaven knows what else. What with all the junk and the river level being fairly low, we did wonder if there was a chance of catching something … Weil’s disease, maybe! At some point I got a sharp bit of old iron stuck into my foot – it having gone straight through the sole of my welly.