Can't see The Hall being a viable attraction on the market as offices again if and/or when the bmi group move out... It's just too far from anywhere really significant with a limited catchment area for a clerical workforce (witness bmi's need to bus staff in from cities/towns in the region each day), too difficult to upgrade to true high-tech standards, and too large for a start up. Only realistic chance of a sale, I'd have thought, was for a major hotel/hospitality chains to buy it and convert it into a hotel cum conference venue
Andy