Visited Stonehenge for the Autumn Equinox 2016 and had a look for these.
Couldn't find any trace and when I questioned an E.H. bod, he told me they were safely buried for prosperity.
"We know exactly where they are and we intend to reinstate them in due time", I was told.
I spent a couple of hours yesterday photographing both Fernacre and Louden Hill stone circles, including making a 360° panorama of each. It was a beautiful morning and well worth the walk with a heavy camera bag and tripod.
I hope it's OK to put a link to the one of Fernacre here as there's no way to add the panorama. (Admin - please delete this if it's breaking any rules.)