Excavation of three long barrows near Avebury, Wiltshire
Paul Ashbee, I.F. Smith and J.G. Evans
is Proceedings of the Prehistoric Society, and one of the three long barrows is South Street, though I couldn't find that on the OS map.
It was in David Field's Earthen Long Barrows I found it mentioned, with no indication where it is apart from Wiltshire, then I found that it was one of the three discusses in Ashbee... then I found it here. Beckhampton roundabout is a stop for the 49, Swindon to Avebury to Devizes.
Something is not right. This message is just to keep things from messing up down the road