Howdo Davey,
I think it's natural although there are some big barrows in the area, and a possible cursus that I've just found out about.
I'm into Wade & his wife Bell big time at the moment.
I'll not bore the forum with the details but if you give me a shout at fitzcoraldo at hotmail dot com I'll let you know what I'm up to and we can have a blether.
cheers
fitz