As has been mentioned the same thing happened at bmi baby, where the redundancy by LIFO was in the contract and was ignored, and BALPA didn't help those who were made redundant by base and seat.
If a junior pilot takes flybe to court for unfair dismissal because a senior pilot is given their position Flybe will lose. If a senior pilot takes them to court for ignoring LIFO they might lose, but it is unlikely if they have complied with all the requirements of employment law, which they almost certainly have.
Unfortunately BALPA should have negotiated redundancy policies before they were needed, now is probably to late.
Good luck to all.