Air France have no interest in LHR beyond CDG, eveything else was dropped or went to CityJet from LCY.
Virgin may look at Moscow and Cairo.
Granite have enough bother raising enough cash as is without a gauranteed loss making LHR operation. I mean exactly who would they be feeding? Feeding STAR was what cost BMI.
Flybe are a regional specialist, I don't see them going head to head with BA.