Visited 15th August 2004: I spotted this stone on the way up the Wrynose Pass (I was actually looking for a picnic spot). As it turns out there's space to park just to the west of the stone, so this is where we ate our lunch.
Then I pegged it back to take a closer look at what I'd seen on the way up the hill. It did look like a standing stone of some sort, with possible packing stones exposed on one side. I got severely rained on taking photos and taking a grid reference (NY2830903302), and just assumed that when I got home I'd find some reference to this lump of rock on the Web.
Now having done some research I can find nothing to indicate that a standing stone exists has been identified on this site. I'm 90% sure it is an artificially placed stone though. It seems extremely unlikely to me that a genuine Bronze Age megalith has been overlooked in such an obvious location, so there's got to be a strong likelihood that this stone is not prehistoric.
Pending further evidence I've put the photos here. Please feel free to pass comment (the best place for this is probably the Forum).