They did !
Norwegian claimed they would base 50 787s there !
Sorry, I wasn't too clear. Any serious supporters.
50 787s is more than the combined total of the based BA,VS, TCX, TOM and DY long haul fleets today. That's like Harry Gooman's Air Europe expansion plans on speed, and just as likely. Norwegian long haul have yet to make a real profit, the whole business is smoke and mirrors.
Gatwick's arguement was predicated on being allowed to expand with Heathrow constrained, Heathrow believes they could expand even if LGW got another runway, mainly because they could still fill LHR at a premium.
BA don't want the competition that a third runway would bring anymore than they wanted VS to be allowed to move from LGW or AA/UA to buy slots from TW/PA.