At the right price there is certainly a market for a bit of competition with bmi (LHR route).
Though it has to be said several carriers over the years have tried LBA-LGW without significant success.
I find LGW just as easy as LHR for getting into central London anyway with the Gatwick Express, tube takes forever from LHR and the Heathrow Express is half the price of the MAN-LHR return flight in the first place!