Well, it all seems that this matter is under discussion by higher authorities in EH.. Yet for my simple mind, there should be no blurring of distinction between what Silbury Hill is (a substantial prehistoric monument) and a need to locate a spurious time capsule inside it. It is this weak approach that is so infuriating. What is happening, are the people in the village (a good half mile away) to be appeased, or is it a publicity stunt.
Historic or prehistoric monuments hold their own history, sadly Silbury had to be ravaged by treasure-seekers and then by a vainglorious archaeologist who knew no better.....
The Swallowhead Spring amongst its 'offerings' had a great deal of tat when I visited it, apart from clay figurines, there was a half eaten apple, a photo of a female in Spain (with telephone number) and a christian missive skewered to the willow. If you wander round the Avebury precincts you will find coloured ribbons, christmas tat, tied to various hawthorns and trees, luckily most of which can be removed.... a modern vague spiritual feeling for an imagined prehistoric past, and it seems that this vague sentiment is to be applied also to Silbury Hill.
If we were to think this out in a philosophical way, we would see that each part of history has its own time frame, which we should respect, tarnishing it with a 'territorial time stamp' is absurd. Avebury Village did not exist when Silbury Hill was constructed.