The sit-start groove on the Flapjack boulder at Caley Crag - I have never got anywhere near it, despite it being around 4-5 grades within my ambit.
I was on this yesterday, looks simple, but does me over every time.
This is ridiculous. I've done it once after a lot of effort and never since.
I've always seen this problem as some sort of grade averaging out because Flapjack Traverse is only about 6C if you've got long arms. There is a way of folding long legs into the limited space available, but I know which of the two I find harder and which one I repeat most often!
I've always found Caley and Brimham hold a few of these for me, although I try then fairly infrequently - the groove rockover thing up at the top of Roadside between Blockbuster and Syrett's Saunter, the sit start to Back Stabber (Pocket Knife?) at Caley Crag, Triangular Roof (left exit to Rachel's Box) at Brimham and Pinky, formerly the hardest 7A in the world, now upgraded and still desperate!