Having gone through it all it seems that on the road past the WKA the verges are getting nibbled due to people having to squeeze by large tractors coming the other way etc. That's a problem shared with tens of thousands of narrow country roads and is solved by having wider sections every hundred yards, (or by placing a few concrete blocks where it's happening) not by closing them, so I reckon there's a bit of kidology going on.

Apparently IF the erosion carried on it would affect archaeology. The crucial word is IF. Prevent it then! I'll put a couple of stones there if they want, it'll stop it instantly, and I won't charge...