Hey Pilgrim,
The Monkton Down drift starts at SU 12304 72507 where there a few stones left.
The fields between that point and Avebury are now emtpy altho every copse or wood has a huge amount of medium sized field clearance stones in.
When the light is low you can clearly see large hollows in the ground all across the fields towards Avebury.
All these views are available as stunning panoramic photographs on my Avebury Grand Tour Cd rom.