From Folkestone Road it looks beyond repair. Certainly worse condition than the recently demolished cinema.
Looking at google's aerial view, there's a lot of land there plus the ambulance station. In another town it would be prime house building land, close to the town centre, railway station, etc. Far better for the town than extending Whitfield.
I would also move have the Customs moved out to Whitfield or Connaught Barracks.
http://goo.gl/maps/AHlH8