I'll check Isis when i am back, it's actually quite tricky to find. In actual fact though, last time I was there the starting hold had broken off, so i think that it may be a short lived "classic". The rock there is a little friable.
The promontory is perfect quality and I can't imagine will change. Another area that i don't see changing is the land of giant but a bit further south. There isn't really anything to fall onto these and the rock quality is very good. The area where the land slip was is directly below a scree of rocks, so it doesn't surprise me really.
Just want to iterate again therefore, please take care in the decent to Land of Giants. It's pretty ropey anyway and this shows that the rock can move.