With reference to the Dunmoor (or Dunmore) Hill Stone Circle (with thanks to Russel Wills for visiting this remote and beautiful spot and drawing this to my attention.
NT9818 : Stone circle and SheepfoldThe original description of this site was as below:
Dunmore Hill NT 985180 Northumberland This site consists of a curved arc of 3 orthostats that stand between 1.0 and 1.3m. high. They are 2.4 and 3.6m. apart. There is a recumbent stone near the central stone and there is an 'outlier' 7.5m. away.
It is debatable if this site was ever a stone circle. [my emthasis]
1: Northumberland County History 14. 65. 2: Burl 1976 (Northumberland 5)
If you look at historic satellite imagery from Google Earth you can see the description above fits well from 2002 (earliest view) through to 2007. The 2018 view shows by then (probably after 2011 which view isn't good) a circle had been put in place using some of the original stones. If it had been me I would have added them to its east side retaining the initial arc. However, such things are not wise as it distorts any true archaeology remaining at the location and future archaeologists might well consider the site prehistoric which it is probably not.
The record on Pastscape (Monument No. 2050, NMR ref, NT 91 NE 24) includes a comment by field investigators in 1957:
"Centred NT 98671810. Position and description by Authority 1 is fully crrect. The stones, large angular blocks, appear to be a group of erratics, and there does not seem to be any significance in the positions they stand in.There are no traces of artificiality. There are several other smaller erratics in the neighbourhood,
some of them 'rolled'."
Megalithic Portal has a similar discussion and further information..
https://www.megalithic.co.uk/article.php/article.php?sid=890A description of the site as it presently stands would be that: "it is doubtful if this site was ever a prehistoric stone circle" although today it is certainly a circle of stones.
Modern view on Bing:
https://zoom.earth/#view=55.45679,-2.022348,19z/layers=crosshairs,nola bels