In reply to Katherine Ross:
Thanks folks. We stopped there briefly today as we were in the area; only did 'The Edge' and saw absolutely nothing (except really small birds flitting about) until we'd both almost topped out, then a couple of peregrines returned from somewhere and flew about a bit. The came and went away again a few times while we ate lunch at the foot of the crag, and we thought it looked like the nest was a bit right of the climbing area, perhaps on the craggy area facing the car park, but it's hard to tell. Decided to head off just in case (plus, The Edge provided pretty good value for a quick visit!)