If I were BA I would just sell it for a nominal price (or a price at least Granite can afford) as this would actual benefit BA
I don't think it's quite as simple as that... Anyone could offer to take Regional off BA's hands for a nominal price, but the men from the ministry (CAA) will require the potential new owners to be suitable to hold an AOC and that they have sufficient funding in place to secure the operation. If Granite can't jump that second hurdle in particular (the former maybe being easier if post holders remain in place) I think any offer they make is unlikely to succeed.