Maybe you should write to EH, get a definitive opinion and transmit the results to those that do it?

After you...

Ok I will.
Or at least, I'll see if Heritage Action will, and publish the results on the website.

In exchange, will you publish what EH say to all your colleagues and ask them to comply?

(This is daft really, as the Charter of Megalithic Webmasters http://www.megalithic.co.uk/sections.php?op=viewarticle&artid=9
and others make it perfectly clear it's wrong and EH have said so, quote - "you need additional permission to leave stuff, which in most cases won’t be granted. Don’t bother asking English Heritage, for example, as they’ve already said no.")