This stone is known locally as the 'Devil's stone'.
I have no idea whether it was a part of the original stone-circle.
Local legend has it that if you circle the stone a certain number of times, you will discover your true love - or some such nonsense.
The stone circle stood in the field across the road from this stone. The 'monument' is shown on the OS map of approx 1900. The OS map can be seen here - http://maps.nls.uk/geo/find/#zoom=16&lat=52.6503&lon=-2.0210&layers=6&b=7&point=0,0
Something is not right. This message is just to keep things from messing up down the road