http://www.visitchurches.org.uk/GazatteerMain.htm
apparently the chancel arch is Norman, so there must have been a church there in Norman times! But the yew trees in the churchyard are supposed to be older than that. Also it sounds strange that the church is on a mound, but maybe if there was a bump in this rather flat landscape (it's the vale looked over from Adam's Grave) then that would be a good place. Kind of suggests the sarsens were on the bump? or moved to the bump?

I'm sure you know I was just winding you up by the way! :) I agree that most 'Christianised Sites' are pure speculation and probably fibs/wishful thinking in many cases.