In reply to Ciderslider:
We met you at the top over the weekend, I think. Forgot to mention there are two distinguishable features to the cave:
1) There is a head-sized hole on its left side
2) On the lip of the cave is a stuck wire with a screw-gate attached to it.
You really do have to walk for quite a way to get to it from the abb that we saw you at.
Hope you find it next time and enjoy it.
Dunc