BA's forecasts will indicate when they need new pilots. They traditionally want a balance of "Cadets" and DEPs.
Cadet lead time, from interview, selection, Flying Schools, BA induction, BA training is a long time.
(Suitable) DEP lead time, from advert to on the line, can be a few months. Stretch this out unnecessarily, and you get all the aggro of a hold pool, as this thread illustrates.
I would guess a DEP scheme opening again that would see the 1st applicants "on-line" at roughly the same time as the 2013 FPP products. 2015? 2016? The DEP start can then be moved forward and back nearer the time as the numbers required become clearer, albeit maybe via the undesirable "hold pool" system.
Whilst working for the airline concerned, I know nothing about it's recruitment, but the above just seems commonsense to me. I do know (and am taking advantage of) we have too many pilots right now, and that is going to take sometime to resolve.