Took ages to find well hidden entrance. It was behind some flood debris in a corner about 10m upstream of the main sink. Once in, I passed several easy squeezes and followed a wire for a while before taking several tiring wrong turns, the last one being extremely wet making me very unhappy as it was scary (water backing up). The way on I think was in a tight-ish looking rift above, but by then I had, had enough.