Yr5 & Yr6 mixed classes

[Primaryworry]

All the children received their letter to say which teacher they would have for the next school year, my daughter is year 5 moving to year 6 in September.
The school are now mixing the classes, so instead of two year 5 and two year 6 classes there will be three mixed classes of year 5 & 6.
The school have some this previous year with year 3&4 but never 5&6

I’m concerned how this will affect the year 6’s, especially since it’s SATS year plus getting them ready for senior school.
Does anyone have any experience in this and was it a positive experience for their child? I can see how this benefits the year 5’s but I fail to see how this can be positive for the older children who are leaving for senior school.
There’s been no explanation from the school just a letter stating the classes and teachers name, no idea how they even work out which child goes in which class, my daughter has been separated from her close circle of friends so she’s really upset about the whole thing.

Starting point: They are moving from 4 classes to 3, so presumably low numbers leading to need to save a teacher's salary.

At which point they have two options: make all classes mixed 5/6 or run one 5, one 6 and one mixed 5/6.

Any year 6 child in the mixed class is likely to feel they are missing out.

This way at least they can strategise and plan for mixed classes.
Maybe they will have 'sets' for maths and English and move between classes.
Maybe there will be less focus on SATs which may well be beneficial.

I think a good school should be able to manage this.
Though some info on how would be helpful, I agree.

In my experience, the Y6s tend to get focussed on until SATs, so one could argue that it's the Y5s that miss out. It seemed to work find in the primary mine went to, but they mixed 1/2, 3/4 as well as 5/6 and had done for many years, so had lots of experience. There were sets for maths.