@narayani it is an authentic Neolithic stone circle dating from about 3000BC. Same age as Stonehenge. It has an outlier or heel stone like Stonehenge, and a rectangular 'cove' of stones abutting the circle. It's in a lovely situation and may have equinoctial and lunar alignments.
@lyndamcg get up early! I got there at 6.52am - I wasn't the first, as there was a track through the dew, but nobody else came into the field, although a walker went by on the narrow road to the A591.