Attended a talk last night by Dr. Alison Sheridan, the Head of Early History at the National Museum of Scotland. After mentioning that 'Wessex archaeology' came down from Orkney and the Ring of Brodgar gaining accepted as being based on Stonehenge (IIRC. else v.v.) she said she had a theory that Silbury Hill had been built in imitation of Maes Howe when that was a much more conical mound. Any takers ?