I had a walk up this bridleway today to check this out. Met a pleasant couple from London who were looking for Ty Illtyd chambered tomb. The 1/50,000 map not showing field boundaries had thrown them off course. You need to go to the farm further up the lane towards Brecon to get access to Ty Illtyd.
There are several suspicious piles of largeish slabby stones on the path. Certainly just the stuff to build a megalithic structure out of. It's difficult to say which of these are alluded to by Jo Williams, as the grid reference could be linked to several of the piles.
I would guess that most, if not all, are field clearance deposit's. They are piled into the hedgerows adjoining the bridleway. This doesn't mean there isn't something genuinely Megalithic here, perhaps mixed in with later deposit's. It's difficult to be more certain. I will post some photo's of different piles and maybe Jo will recognise the one that aroused suspicion in the first place.
Something is not right. This message is just to keep things from messing up down the road