In reply to Clare:
so did they get to the top???
I think so.why:
well,when last seen they were high on the ridge having just gone over a rock step.
This was not the first step.It could not have been the second step,because its a climb,plus they were seen on top of this step /bulge.
If that was the 3rd step,then i see no reason why they would not have got to the top.
Well worth looking into the books written on the subject.
A