In reply to ColH72:
Sinister Gully is about 10m to the right of the wall, has a small section of dry stone wall in its lower reaches and a curling overhang high on the right wall. Dexter/main gully is about 15m further to the right of Sinister and used to have a rickety, turf covered stone arch at its exit which collapsed a year or two ago. There is another, easier gully to the left of the wall, round the corner a bit at the top of some scree.