I can't quite get the profile of Silbaby....only what appears on the photos that have been posted....Baza seems to imply that the road and top of Silbaby are at the same level....Is it a distinct feature away from the road? I was thinking more that if a cutting was made the removed material was put somewhere and Silbaby is the result.
I live quite a distance from Avebury so am running on guesswork at the moment so forgive confused ramblings!