"A c.40m diameter subrectangular ditched enclosure" (see coflein link above) was indicated by surveys in the area of the stones. I don't know what this really means, but if it was a rectangular stone-built construction, either smaller, and in the centre of a 40m diameter ditch, or the construction itself filled a 40m diameter - like a field - then the stones possibly could have been used in its construction? Perhaps there was something more 'special' about these three and they decided to save them?
I'll post the rather basic plan I made from my dowsing on the day. This is part of an on-going experiment to find out whether doing 'ritual movement' dowsing at megalithic sites can help find out any more about their original construction. (I ask to be 'shown' where the ancients moved during their most important ceremonies when the site was at its most important.)
You'll need to blow up the pic to fill the page as A5 (I tried this out) so you can read it, or maybe rotate it to print out an A4. All moves are numbered in sequence, and the different colour ink is used to help distinguish progressive sections.
The site slopes to NW approx, and I had no idea I would be taken in a circular movement when I started by 'Enter' at the right of the largest sloping stone. (Coming from a direction of 290 degs - behind me). At the 70 degree point on the arc the rods turned me towards the 'centre', moving in the direction of 220 degs. There were 3 tighter clockwise, followed by 3 tighter anticlockwise movements side-by-side at the centre, then I was taken in a wider anticlockwise circle around the tree. On the other side of it - approx SE near the tree - the rods moved me in another tighter triple anticlockwise swirl. Maybe this would have carried on with a matching clockwise swirl, (I often find this sort of mirror-image movement, the same pattern only reversed, each side of a stone) but I was tired then.
I'd also dowsed out from the 'centre' near the tree and found seven consecutive openings of the rods with the seventh by the remaining stones. I hardly ever do this these days but, when I first started dowsing, this was the normal result when dowsing from centre to edge of a circle.
Walking around the perimeter of the 'circle' twice was difficult because of the undergrowth, but in one pair of photos posted you can see the approx position of the East arc where my backpack is sitting. On the plan this arc is pencilled in.
I have much more complex plans than this one, but even basic ones like this are worth considering, just in case they can teach us something about a site. I am pretty laid-back about these findings, and only want to share my results. (Not trying to say I'm proving anything.)
Something is not right. This message is just to keep things from messing up down the road