I think the BA pilot community would see a higher proportion in the 25-39 bracket as a result of the high level of cadet recruitment pre-2001. There's (statistically speaking) nobody 60+ flying for BA either, although that will change in the future. It would be pure guesswork to say how that would affect a long haul command in 20 years time. BA have in the past tried to spread the demographic profile of the pilot group in order to avoid a bulge in retirements but as far as I know it's nowhere near as precise as you speculate. With the abolition of a compulsory retirement age it's probably not a problem any more, and age discrimination legislation probably makes that kind of selection illegal now anyway.