"I wonder if anyone has considered the diameter of Stonehenge in relation to the diameter of the summit of Silbury"
We've done all that loads of times LS, now its fitting Hadrian's wall in the Silbury Tunnels....
VBB
PS Corse they nicked stones for Stonehenge from Avebury and Manton and Stanley ! All the big-uns had gone by the time they got round to |Stonehenge so they recycled !