Sponsored signage is not such a new idea (and there are green plaques as well as black plaques by the way which have nothing to do with English Heritage). So, given that Silbury is privately owned, sponsored signage ‘might’ be the way to go - but only after twisting EH’s arm around its back to do it first.
There was someone from EH on Radio 4 a couple of days ago trying to explain English Heritage’s reasons for shelving the blue plaque scheme. One bit of interesting info to come out of the prog however was that The National Trust might take over some of the BP responsibilities from EH.
So there you have it; when it comes to Silbury we have English Heritage, The National Trust, Lord Avebury and us lot all with a vested interested in getting something done re: improved sinage – failure to do so is not on the cards.