what amazes me is that is seems no bugger else has even looked for these stones!
Bluestone must stand out if used in a bridge or a wall, even if it broken up.
The large missing sarsens could make several walls of a house.
Pitts thinks they are in the foundations of Roman buildings (where?) or buried. well there are no buried nearby as recent geophys would have found them.
In my experience most farmers don't know what they have got on their land.
PeteG