"A new charter to cover all ancient monuments and stipulating to the landowner exactly what his responsibilities are?"

Well it would be a hoot, wouldn't it, if a bunch of megarak scallywags codged one together here, and published it on HA and elsewhere without the slightest consultation with official guardians. One is obviously needed, bearing in mind the recent fad for generating income from film companies and advertisers, yet there have been umpteen instances where the thinking has been pretty haphazard.

Personally, I think simple is best and Lord A's words cover it pretty well. Keeping to those would have avoided all the recent nonsenses.