I activated this one way back in 2007… can’t say I’ve ever been tempted back there. 
Sighty Crag SB-005 and Blackwood Hill SS-199
That final 1.2km is indeed the killer. I think the easy forestry tracks lull you into a sense of false security. When I did it the forest was still extant and it was a relief to get out onto the open hillside, the feeling soon to be dashed by the yomp across the heather and rocks. I’m sure the undulating route added 50m of vertical height!