In reply to Rob Laird:
yup over the stile off the ridge and zigzag down, once you loose the faintly visible path head straight down and theres a stile crossing the wall then head diagonally down left and youll find the path again quite soon. Its not a pleasant descent but its the most efficient way down and crosses directly to the path up Elidir fawr (oh the joys)
Tip for Elidir fawr is cross the road towards the campsite but follow the road around to the left and up and before you get to the farm turn right along the footpath uphill, that will take you on to another faint path, when this comes to a zigzag, go straight up rather than following it left and youll come to the main path. Follow this up and around and youll come to a small footbridge crossing the river. The path continues up from that, a bit vague in places but you should find it ok, it gets clearer again as you ascend (seemingly forever).
Post edited at 19:47