You prompted me to go and have a good look on google earth (for the eleventieth time) and I'm remembering a comment from V about another road from the campsite being higher and having a good view down.
They came in from the north east / Leadore direction on the 172/172a, and from looking at the elevations the more southerly road (172/207) is the higher one. It skirts the reservoir and continues on but is ultimately a dead end from what I can see. The exact camping site is where the yellow pin is on this picture.
Since there is some debate about whether there were 1 or 2 trips to Leadore that day, could it be possible that one of those trips was in fact further along that high road, in the opposite direction to Leadore? Also, is that the road V "hauled up" when he was trying to get a signal? I has always assumed he headed back towards town but maybe not.
Sorry if this has been covered already!