I read somewhere that the Open Aspect issue wasn’t intended and arose from insufficient detail on a zoning plan, but can't confirm that.
What annoys me is that it’s hard to imagine Skanska taking such a long time if they were working for a “proper” client, surely? Is there an agreed contract price or has it been left open-ended? This is EH, so let’s guess. Guessing is all we can do as all Silbury discussions in their minutes are barred from public release.
Also, IMHO they’ll come up with the obvious solution that was there from the start: pumping in a rock aggregate paste of similar bearing strength to fill all the voids. It’s totally tried and tested by Ove Arup on the collapsing limestone caverns under the West Midlands, and it’s really quick – Moth’s single week is about right as they have mobile units to make it on site. It’s totally un-intrusive since it simply replaces fresh air, not archaeology, and they could colour it red for the benefit of posterity. EH had a junket to Sweden to study a new method but that would be against there own guidelines which require the exclusive use of non-experimental methods, so the trip and the delay, both of which I paid for, along with their annual Xmas dinners, are a bloody cheek.