Fantastic, thanks that is just what I was looking for.
I have visited Avebury and Silbury hill a couple of times before but I was unaware of all the other nearby features at the time.
So if I park near Avebury and walk down the West Kennet Avenue will it lead me all the way to the Sanctuary or have some of the stones long since disappeared?
On the map I see that if all the Avenue still existed I would need to cross the B4003 and then the A4 to get to the Sanctuary.