Very interesting insight, thank you.

Quite a few of these jets were meant to be supposed to be retired in 2022 (G-EUOF and G-EUPJ being some I can remember) so it's no surprise they are biting the bullet now.
Seems like all of the G-EUOx A319s will be gone by the end of the year if all goes to plan, they were the newest ones delivered directly to BA. (Even though age doesn't really matter in the context of aviation, it's more about maintenance)
Most of the A319s retired are the ones with no Wi-FI (with the exception of EUPY/Z and EUOA)
Will definitely miss the little A319s, but replacing them with bigger and more efficient A320neos makes financial sense.

The G-GATx fleet shrinking is quite intriguing however not too shocking considering these are aircraft which are 20+ years old and also used (unsure whether that would have any impact on the decision though).

It seems that there are some significant changes planned for this year, interesting to see how it will all pan out.