I can't see how they would be able to police that one Roy as they can't currently stop people climbing Silbury or MDing SAM's and that takes a whole lot longer than a quick flight over a monument from the edge of a field.
I have a tracker on mine and I could potentially land it almost anywhere and then go pick it up later.
Also I can't see how they could get away with claiming ownership the sky above a SAM. However they may get away with on some sort of health and safety grounds if it is a busy site such as Avebury or Stonehenge.
Didn't EH try to claim all photo's of Stonehenge belonged to them a while back or was that just media hype?
:)