All they need to do is re submit the application to Hillingdon, and it will be accepted as it has passed to the appeal stage. The only reason why HAL will delay again is that the residents of Cranford will suffer a huge unacceptable noise burden, likewise in adjoining boroughs, which is what will happen should R3 go ahead. Easterly ops form 4.30am continously to 12 midnight on one runway.
Extant planning permissions can be revived, a common practice.