I imagine (having gone through restructuring) that they are looking with a cold heart at what can afford to go.
Additional admin staff and TAs for non ECHP children are fairly high in the firing line if the choice is 'TA to every primary classroom and lose a teacher' or 'have a teacher per class and trim support staff'.
I'm not saying the job isn't valuable. I was support staff in school prior to teaching but that will be someone with their figures head on.
Some schools I know have forced PE/creative arts teachers to pick up additional hours teaching ks3 humanities in their timetable because it means after someone has left they don't have to employ another teacher because of budgets.
Even contracting out some stuff can be cheaper because the school won't be liable for sick pay, maternity pay etc.
The issue on retention payments is that the school's currency, so to speak, is it's outcomes, teaching and learning. Lose enough of your strong teachers and the quality of of teaching declines, behaviour standards declines, results decline and when a school is on that trajectory parents stop sending their children there so you have 75 spare places in y7. After a couple of years a school with 800 capacity has 600. Then Ofsted come in because it's a school in crisis & it gets slammed and more parents pull their children out and before you know it you've got a school at 50% capacity, most parents don't want their children there, lots of staff won't want to work there and then the school faces closure or being gobbled up into one of the mega trusts.
Restructures and potential redundancies are crap all round, but I think taking the view this is personal against a sub group of staff is a bit much. You need to have your union subs paid up to date and with the skills you've got ride it out.