I’ve not visited this site, or even seen any photos of it, but Michael Dames refers to it in his book The Silbury Treasure writing in the chapter Neolithic Harvest Hills in England:
Surviving members of the same class [as Hatfield Barrow] may include the enormous structure on Silk Hill, Wiltshire – a large circular mound 135 feet in diameter, 18 feet high, and encircled by a ditch. This edifice was opened by Hoare, who doubted whether it was sepulchral. There was no sign of internment, and the only finds were ‘animal bones of deer etc.‘
If Dames is right, the Silk Hill Mound is essentially a scaled down (and simplified) version of Silbury Hill.