I think you'll find those mill stones are the same that Thomas Hearn claimed came from that massive 'tolman about close to a mile away south at Marden Cowbag'. From your horse you'd be able to see them still lodged in the hedge 'over against the trackway up to Stonehenge'. I know Isobel Smith once claimed them as the remains of some massive chambered tomb, but ages ago when I was still a student on a routine Avebury dig she told me she'd really revised her opinion because the capstones could have never been big enough.

I'm off to Scotland for 5 months in the morning, but when I'm back my mate and I are planning a bit of hush hush clandestine digging at Hues Farm at Beckhampton. Those 2 massive capstones in the base of the Beckhampton Penning barn are exactly the same size and shape as Aubrey described as having been 'spirited away by persons unknown as tho twere a great kindnes done to the Abury Townend to be rid of them'.

By the way, the stones in the porch at Manton were removed on a medieval ox cart with no particular fuss. This idea that sarsen stones are hard to move is a modern myth. How do you think the downs were so depleted in those days before motor vehicles.