Well if you look on some of the Old Ordnance survey maps (find them at http://www.old-maps.co.uk) you will see how the OS defined the camp then compare to google earth and you will see some of the camp visible as cropmarks, see 1999 data for north/north east section, then see 2003,2004, 4/2005, 2006 for other areas.
It is better with the low sun and the crop growing, as I found last August at harvest time. I'm having trouble processing some of my oblique crop mark images into verticals.
Something is not right. This message is just to keep things from messing up down the road