I've only been up there once and that was in the early autumn, the heather growth wasn't too high (about the same as the photo's on here) but as the stones are quite small and given the size of the circle they tended to blend into the landscape somewhat. It is gorgeous up there though and definitely worth a visit, the track leading northwest from Wayworth Farm passes within a couple of hundred metres of the circle and is probably the easiest approach to the stones.

-Chris