Great work bladup! I visited yesterday and was blown away by the size of the stones you found. Your pics gave no idea of scale, so I’d expected them to be much smaller. I measured the 6 largest stones – average length was 2m and the biggest was 2.7m. There is a lot of confusion about this site, even though it was shown on OS maps for many years. I feel sure these are the stones, but not the original site. I can see why you thought it was the original site, as it so much resembles a collapsed cromlech – but it is a random pile of sarsens that have been dumped.
The barrow was definitely sited at SU 15137140, which is now in a ploughed field, some 300m to the NE of your stones. The remains were bulldozed flat by a new tenant farmer in June 1952; the destruction was not witnessed by CT Barker though. He was not local and I believe he lived in the Midlands. There was a national outcry – the destruction was described as a scandal by The Times – as the farmer had not be told by the NT that there was anything of value on the farm that must be preserved. He was advised to put the stones in a patch of scrub near the site at SU 1513 7141 (as described on Pastscape) but the scrub has long since gone and the site ploughed flat. The stones were obviously taken away, but no-one knew where to.
CT Barker wrote a lengthy article ‘The Long Mounds of the Avebury Region’ published in WAM Vol 79 (1984) in which he claimed that the original OS position of the barrow was wrong, because he had found the remains at SU 14787135. This was dismissed by Peter Fowler, who was an acknowledged expert on the area. Fowler thought the stones may have been moved there by bulldozer, which is probably correct. He doesn’t appear to have visited though.
Pete G & I made many trips up there last winter, looking for Barker’s stones. Although we deliberately went when the undergrowth was at a minimum, all we found were the many field clearance stones to the W of your site, so we wrote off Barker’s claim. We were less than 20ft away but didn’t see what you found! The brambles you removed must have been very thick. We found several other piles of large sarsens all around the original site, but none were big enough to match those on plans of Manton Down LB by Piggott or Lawson & Passmore. I think yours do fit the bill.
There is still a puzzle though – Rev AC Smith witnessed the splitting of the capstone by workmen in around 1885, but I couldn’t see any sign of this. However as well as the 6 huge stones piled up now, there is at least another large one almost completely buried in soil: perhaps the two pieces of the broken capstone are buried there?