I think some here are missing the point.
LIFO may well be acceptable, but in BA's case consider:
1. Is it advisable to make redundant, and replace, a cheap junior A320 FO with a senior A380/747 FO (who's role has become redundant)?
2. Will BA want to incur the cost of re-training a senior B747/A380 FO into the position of an already trained a ready to go cheap junior A320 FO. Why would they want to incur ANY cost when they're haemorrhaging cash?
3. As this situation is such an unknown, will BA want to get rid of a load of cheap junior, ready to go (other than a recency sim) A320 FO's and have a pool of 747/A380 senior FO's waiting round to be go through a 4-6 week training course with aircraft unnecessarily sitting on the ground?
I mention A320 above because that's where most of the junior guys start. BA is a corporate animal. I'm sure it wouldn't bat an eye at having to make some brutal decisions over the coming months. People say BA have never made pilot redundancies - problem is, this is a very different BA. As much as this situation is hurting BA I'm also sure they're looking at ways to manipulate it to their advantage.
I sincerely hope BA keeps everybody employed but there are difficult days coming.
Good luck to you Virgins too 🤞