Well according to the first lot of notes here, no prehistoricness at all. http://www.themodernantiquarian.com/site/3446/stantonbury.html
here near the top of the fort... http://www.themodernantiquarian.com/post/45812/hinton_hill.html and here on the east side of the slope.. http://www.themodernantiquarian.com/post/45813/hinton_hill.html
Indeed. Until I read that and looked for more info, I was convinced it was directly linked to Stantonbury. On closer inspection there are no ditches and the earthworks aren't contiguous.