The stone that Keiller put the other way up was one that Maud Cunnington originaly erected on the Kennet avenue.
Keiller decided it was the wrong way up because when he excavated the base to prepare it for a concrete platform he noticed the stone didn't fit the socket so he up ended it.
Some thought that he did it to get at Cunnington who he had a long term row with.
If Keiller never worked at Avebury it would now look much like Marden henge but with more houses.
PeteG