And the loss of the car parking is going to affect the theatre too.
I think the council's requirement that 'any redevelopment proposals will need to incorporate sufficient car parking provision' should take care of that.
If a supermarket isn't interested, the council document lists a number of other possible uses:
A2 Financial and Professional Services
A3 Restaurants and Cafes
A4 Drinking Establishments
A5 Hot Food Take Away
D1 Non Residential Institution
D2 Assembly and Leisure
C2 Residential Institution
C3 Dwelling Houses
Some types of Sui Generis use e.g. Night Club, Casino