But, how do English Heritage interpret setting? Is it hundreds of meters or nothing at all, which I think Tarmac will suggest - purely the land holding the archaeology.

When you look at what is protected in this country be it national parks, or 18th c houses, it becomes clear that there is a lot of land that is given special status and protected. Castles - Carew Castle and Tidal Mill for one, is beautifully situated with the land around free and open, so archaeological remains should be given the same status, and plenty of space. EH have plenty of examples in how landscape fits in with upstanding monuments, abbeys, roman remains etc, it should'nt be too difficult.. Priddy henges, knowlton henge all survive well, Tarmac must give in eventually.....