Thanks for the replies (esp Baza for the Stukeley stuff).

When you do go, please bear in mind that there is barbed wire all around this site, and the field is full of cows. It's not that accesable, desipte being right by the roadside. There is a small wooden stile in the trees though, (but syou can't see it 'till you're in the field). Perhaps the farmer dosen't want visitors?