The earliest Wiltshire standing stones?

 The illustrations from the Cunnington article of 1924

On p 59 of the new book by David Field and David McOmish, there is a mention of three long barrows -- assumed dates around 6,000 - 5,500 BP -- which appear to have had standing stones or foreign stones built into them.

One of these is Boles Barrow, and in referring to the Cunnington observations, the authors seem quite happy to accept that the old fellow did indeed find a bluestone boulder inside it. Was it the "broken" boulder currently in the Salisbury Museum?  Others have of course suggested that if a chunk of a larger standing stone went to Haytesbury House and ended up in Salisbury, maybe the rest of the standing stone is still there, inside Boles Barrow, or maybe somewhere nearby?
William Cunnington, who dug into Boles Barrow in 1801, died in 1810.  Here is the original record from Howard Cunnington, in The Wiltshire Magazine, June 1924:
https://archive.org/stream/wiltshirearchaeo421922192#page/n477/mode/2up
 
He was of course completely certain that the provenance of the stone was correct, and that it came from Boles Barrow, and not from Stonehenge.  I too am convinced -- the documentary trail is completely authentic, and the only debate about provenance related to a piece of granite that appears to have had nothing to do with either Boles Barrow or Stonehenge.  HTT of course confirmed that the Boles Barrow stone was spotted dolerite, virtually identical to the stone which is well represented in the Stonehenge bluestone assemblage.

By the way, wasn't there supposed to be a definitive geological study of the Boles Barrow stone, with new laser imagery and new petrography?  I know there was some work reported in the Carn Goedog paper, but I thought there was more on the way......... (we had a bit of a chat about it back in May).

The next one is a long barrow at Arn Hill, near Warminster, on the chalk escarpment, which had "a standing stone set within."  No radiocarbon date, but the earliest example of a standing stone in Wiltshire?

The third one is at Knook, where the authors seem to think there was a standing stone which was later broken up, and the bits incorporated into the long barrow.

I know Tony gave us a steer on all of this a while ago -- but does anybody else have info on any, or all, of these sites?  I tried to find the EH scheduled monument records, but didn't have any success......