It wouldn't offer airbnb rooms if it were being used for its intended, and planning approved, purpose. It is currently being misused - that's the point - and for short lets instead of long-term living for older people. There was very little marketing for its intended purpose, as revealed by residents who are keen to see it used as it should be. In addition, the internal specification was disappointing in relation to the price of the flats (based on a slight attempt to mark them, early on in this process). There is demand - but not for over-priced poorly-fitted flats that assume older people want to recreate a long-gone era rather than live in the modern world with modern fixtures and fittings and decor. Everyone is currently waiting to see what happens next now that the latest planning application has been refused. You are right, though, that its current misuse and other enforcement issues wouldn't make it easy to sell the flats - but they aren't currently being marketed and you can be sure that, if they are marketed in their current state and don't sell, residents will emphasise the fact that the flats cannot be seen as desirable given the state of the building and its grounds and the internal specifications.
Joanna Biddolph ● 9d