AR and GD dived through sump one, as it was AR’s first cave dive GD carried the srt kits and gear for aid climbing the 80m aven which was the aim. After a hot brew we headed upto the ledge found a few days earlier to assess the aven. Using a tight beam which AR had brought showed that the holes that GD thought existed were more likely to be overhangs. With AR being the more compitent climbed first lead using slings to give a vantage point some 25m up the Aven (the ledge being at 11m), this yielded no prospect. A second area of the aven was climbed second and at the top of the first pitch GD joined AR at that appeared to be ongoing passage. After a short distance the roar was found to be the stream some 20m below so it was just a continuation if the downstream passage. AR then belayed GD around a traverse to see if an opening would yield passage, a small tube was acended for 3m to a mud filled conclusion. AR then lead again using aiding gear to reach another shelf at some 47m above the floor. This was time consumisng as the rock was poor and use of naturels was difficult. No obvious leads or a draught was noted. With little prospect of passage a return to the surface was made after 12hrs underground, with he rope was left in place.