Leeds - London only takes 2 hours on the train, with fares from £33. BA will never be able to compete with that. Leeds is also very close to MAN so will inevitably lose connecting pax there.
I flew LHR-LBA last month and saw a load of around 50 people on an a319, on a Friday afternoon, going Northbound, very poor load... LBA doesn't exactly lend itself to the business traveller either, the place is a dump!