Sidetrack Cave has an unusual access procedure which involves abseiling down the side of a quarry to get to the entrance. Kathryn and I decided that this was enough of a novelty to warrant a trip in itself.
After half an hour of wandering along some dodgy ledges in completely the wrong part of the quarry, we eventually found the right spot for the abseil. Watching the rope sawing across sharp edges of quarried limestone was a little perturbing but we made it down safely.
The cave itself starts off with 100m of flat out crawling, with a few puddles thrown in for amusement (well I was amused anyway...). The passage was probably once 2-3m in diameter, but it is now full of mud to within a few inches of the ceiling, so there's no choice but to squirm through on your belly. Eventually we reached a T-junction with a walking-sized passage. We explored in both directions and looked at some quite nice formations, although I think they are starting to get a bit muddied and damaged in places.
After a few photos we headed back out and prussiced very gingerly back out of the quarry.