Have those 'druidical circles' on Thorney Island and by St. Pauls, described in E.O. Gordon's "Prehistoric London" (1914) ever been substantiated? He mentions a few other good old heathen places aswell...
I just picked up Gordon's Prehistoric London (a bargain at £14.50) to find
(Oi NIGEL ARE YOU LISTENING !!!) ahem,
p.45-p.96 is on "comparative antiquity in Wiltshire" which has loads of stuff on Silbury and Avebury and Stonehenge.
If that don't cap it all... capital, just capitol.
VBB