In reply to GrahamD:
Retreat – hmm, tricky. If you’re thinking of giving it a go on Sunday and failing, I’d take Monday off work.
I see the programme something like this:
Step one: leader fails. Lower him directly into the sea. Leader splashes to shore and belays.
Step two. Second abseils into sea using a single rope and is hauled to shore by leader using the other rope.
Step three: Both climbers remove and abandon gear save for harnesses, abseil devices and prussik loops (you will need these later for my plan).
Step four: Both climbers swim to the bottom of Castell Helen.
Step five: Both climbers solo Lighthouse Arete. (or of course, one of you does this and throws down spare rope to shivering partner)
Step six: Revert to top of Yellow Wall and fix abseil.
Step seven: Abseil down to retrieve gear. Discover that crag overhangs to extent that you cannot get into land. Prussik back on abseil rope. Scare crap out of self.
Step eight: Having reconsidered, abseil down again into the sea. Struggle to land. Retrieve gear from there, and prussic up the abseil rope you used in step two, remembering to use some kind of device on the first abseil rope.
Step nine: on arrival at belay, clip into same. Pull up the abseil rope you’ve just prussiked up. Coil it.
Step ten: clean belay, having first made sure you are attached firmly to the abseil rope.
Step eleven: take almighty swing out over the sea. Soil yourself with fear. Eventually come to rest and….
Step twelve: prussic back to the top carrying the two climbing ropes and the entire rack.
You may want to draw lots for some of these tasks before you start. Should provide good motivation.
jcm