I presume you've looked at the Coffin Stone in the field opposite the Countless Stones. Walk around the farm from there on the footpath and accidentally peer at the lovely rock garden / pond in their yard which was apparently a stone feature around a spring.
A corresponding one was destroyed by the water board at tottington spring(?).

I also remember reading about a destroyed circle near the river medway.

Its been ages since I've lived in South London though, so my attention has been refocused on to sites I can get to easier...