Before discovering the new bits in Treak Cliff, myself and Markc of this parish did have a wander around the hillside poking and prodding various holes. We did attempt to dig out Tree Hole or where we thought it was, but we gave up as we think we were digging just a scree pile.
However, after Markc moved to South Wales, I was wandering around in Treak Cliff Cavern, and just past the first set of steps in the entrance series of the mined bit, on the right there is a muddy track to natural, after scrambling underneath the natural, you look up into an aven/chimney/shaft thats blocked to the top with large angular stuff (i.e. waste).
Having a poke around with a certain J.T. of TCC on the surface, we found where the shaft breaks the surface - albeit covered in scree - was this the first entrance before they drove the level?