>> I think if a builder was going to put sarsens anywhere it would be at the corners. Unfortunately, that's
>> also where you'd put them for ritual reasons too.

Can't see any reasoning behind that statement, to be honest. I would have thought that the two places you would put them for 'ritual' reasons would be at the entrance and behind or under the altar (i.e. round the back).

Placing them at corners would define the modern sacred space with bits an old one, but the corners have no Xtian significance. The door into God's house and the altar do have though.