I don't believe that for a second.
A load of the Cityflyer guys said the exact same thing Anton, and most (I'm guessing about 80%ish, but willing to be corrected) are now co pilots on LH.
It remains to be seen, but I'd be willing to bet the same thing will happen with the bmi guys despite what you say. Most of the bmi guys I'm guessing won't have done much LH, and it's safe to say that BA longhaul is very different to what the others will have done in bmi.