Interesting post wireless you could do with a holiday. The sleepy folk are of the view that the worst problem for Nigel's is that you very rarely work the same schedule, so planning rest periods get very difficult albeit each individual manages it in their own different way. So a shift worker working earlies / lates / nights or days / nights know exactly what to do as there isn't that much variety. Then Crews have to deal with TZ transitions (sorry to say EASA FTL is much better than CAP371 in this respect), jet lag, delays, commuting, other hobbies / jobs etc.
I know a lot of LH crew who have worked out that staying adapted to UK local is often needed to manage such schedules - you have to be pretty hardcore to manage this though although the rewards can be you recover in BA's time rather than your own.