Intrigued, I went out there today to visit the 'other' Adam and Eve. I go past on the bus weekly but its a while since I'd actually walked over there. It's a lovely walk up through Avebury Trusloe and along the quiet road with only the swooping swallows (house martins) for company. As you are aware I'm sure, there is an excellent interpretation board by the stile over into the field where Adam and Eve stand. The information board says they are the only visible remains of the Longstones Cove and Beckhampton Avenue. From the diagram it seems that Adam was one of four cove stones and Eve the last of the paired stones which made up the Avenue. So they are not even a 'pair'.
Its easy to see where many of the stones ended up when you see the sarsen stone garden walls on Bray Street leading out of Avebury Village.