"..... we have to allow for reasonable expansion-preservation and growth of the BA hub, rather than just giving the game to Emirates....."
A) Do we really?
B) We? Surely this is a purely commercial concern between two Anglo-Spanish companies (IAG & Heathrow Airports/Ferrovial)?
C) Surely if expansion was in the plans then building major infrastructure and housing all round about the boundaries of the airport would not have been permitted, either by local authorities or by national government way back when it was a national asset before privatisation in 1987.