In reply to Iain Thow:
On Friday Alan and I climbed the Twin Ribs first and then we found another, larger buttress 60 m further south, just before the start of the steeper part of Fiacaill Ridge.
There we climbed a prominent 25m gully on its right flank, broad at first and then narrowing and steepening to maybe 70 degrees, and finishing on the top of the buttress and the path up Fiacaill Ridge. A nice, maybe grade III climb to access the Fiacaill Ridge.