It could be a case of a mistake committed by a contractor. Who knows?
Aye, could be, all the more reason for English Heritage to clarify things – they are, after all, working for us not themselves ;-) Put another way, those concerned with the conservation (and better understanding of ancient sites) are us lot here and on similar boards (as well as a sprinkling of archaeos working within that timeframe).Put another way, if someone had bulldozed the only one of its kind listed building there’d be a hue and outcry in the media, and those under whose stewardship said building resided would be called to account – pronto.