I've searched through my books and cannot find a name for the mound or the spring.
I have a panoramic of the hill here
http://aveburytour.mysite.freeserve.com/Silbury/MiniSilburyA.htm
but I'm currently having problems uploading new pages.
Stukeley did a sketch of the area and draws a circle like a pond barrow cut in half by the roman road.
Its obviously not a pond barrow and it very much a mini silbury to my eyes.
Anyone want to put a name to the spring or the mound?
PeteG