Nigel,
A professional Mediator told me that a successful Compromise is acheived only when both parties leave the table Dissatisfied. Judging from this thread I think we are just about there with the current SCope Clause.
We have to remember that SCope also deals with Franchising, Subsidiaries, Freighters, Alliances, Codeshares and mergers. If the aircraft size is such that BA have a huge flexibility in various aircraft-types available then you can sure as heck bet they will use all the tricks in the book to avoid using a BA Pilot on BA T&C's to fly as many BA routes as possible with outsourced Pilots(not necessarily ex-BRAL always).
If Scope however is agreed and BA do require more or larger aircraft, then they will also need a greater # of Pilots which would have to be employed on BA T&C's....these Pilots I would like to see come directly from your crews and I'm sure that is the intention anyway. Perhaps that is what BALPA should also be trying to secure with SCope, a 1st refusal for any new employment in BA. That way you guys can all be 100% sure that it is YOUR future you are securing with the Scope deal. Why not give your CC Reps a call to push home this point.