Thanks June, that was the service I was looking at, it certainly looks do-able doesn't it? It probably needs a bit more planning though (and on a weekday I could get to Swindon earlier - 7:30 - which might open up better options).

My biggest question is probably "how accessible is the landscape around Stonehenge?" as the map doesn't seem to show much in the way of either footpaths or access land.

I'll probably end up somewhere nearer Avebury, maybe Cherhill or a return to Devil's Den and Fyfield.