are you sure they didn't? Not that I don't believe you ...
I mean, I've got no idea about stone-burning. If you don't actually try these things out properly, then you're riding on an assumption. You've got to use a stone from thereabouts, otherwise you'll get misleading results.
I wish I'd seen this prog years ago, when I used to work in these woods - one of the jobs was rebuilding barbed wire fences, and to firm up the stakeposts, we used to use bits of stone at the base, below the soil. Right bastard of a job is breaking stone ...
at what distance from Avebury/Delling would people say it's OK to molest the stones then?
RG