Forget about Agebury for a while ...
While I was waiting for the moon to burn through the rainclouds at the weekend I kicked moss off several buried stones at Thurstones. The bank of rubble protects them but they stick out the top. None of them are a hundred tonnes but one could be seven or eight - pretty big for Bolton.
Also found a 'ceremonial hill' named Toothill, in Halliwell, with a crecentish-shape. Clear view of the SSE horizon (still). Houses on three sides. It's one of the reputed sites of the Knights Hospitallers' infirmary - the other is a quarter mile away, at Holy (H)arbour.