In reply to steveb2006:
> I would have thought if it fell under its own steam as it were, it would have made some distinct marks on the slabby wall below and also on the ground below. But there are none. The remains of the block are lying in the bracken about 3 or so metres away from the base of the crag - suggesting it was pushed out with some force.
I photoed the wall last spring and the block was still there, when we revisited in the autumn it was on the floor. The main chunk was pretty big, I doubt anyone could have lifted out and thrown it, I suspect it was levered out and just 'kissed' the slab on the way past,
Chris