BA has a pretty rotten structure altogether. I just did an A320 Type Rating revalidation on my EASA license with a BA 747 FO. He was trying to get some protection for possible redundancies. The reasoning being that BA does not let people go based on seniority, they let them go off of certain fleets, seats, and bases, and based on their qualifications on other BA aircraft. So if he was qualified on the A320, it would give him more of a fighting chance to be switched to the A320 fleet if there were any FO spots available. As it stands now, a senior 747 pilot would be let go before a junior A320 pilot because they are reducing the 747 fleet, but not the A320 fleet (at least not for the time being). Even before this mess, BA had different contracts based on which fleet and which base you were at. A Heathrow based A320 pilot would have a much better contract than Manchester based A320 guys, and that contract would be better than the Gatwick contract. A completely convoluted structure.
Of course the Brits excel at making simple things more complex than they need to be. If you need an example, their tax year runs April 5 through April 4. Not January 1 through December 31. Not April 1 through March 31. April 5 through April 4. It causes a lot of headaches when trying to file a UK tax return.