When I got to Calne I found that there is a regular bus route to Marlborough, via Cherhill village and Avebury, but I couldn't be bothered to wait for an hour or so before setting off! :)

But would definitely make use of that with better planning another day.

I like the fact I've now walked to Avebury from a different direction each time - from Barbury Castle via Devil's Den and Fyfield Down, from Shepherd's Shore via Wansdyke, Allington Down and the Sanctuary/Avenue, from Broad Hinton via Yatesbury and Windmill Hill and now via Cherhill Down. Certainly has given me a better appreciation of the landscape surrounding the henge.