A very sad day, and 109 is a far cry from 85!
Regarding regional, while it may not be very popular, these were the terms agreed between the various parties. Its a bit late now to start making noises, other than to cause a 'them and us' attitude to breed, which achieves nothing.
Unfortuantely for the cadets, if they had signed a contract, effectively waiving their length of service for the company, then they have to accept the consequences of their actions, unless BALPA can sort something out.
You will probably find the LIFO principal is really the only method open to the company. After all, those who have tried to make redundancies on the basis of age, sex and even productivity have all had their fingers badly burned.
Anyway, redundancy is never fair to the person at the receiving end. I've been there once too often already.