It's not illegal if they send a simple email the same day to confirm it's a PEx.
Which is what happened.
So the either the school have a big enough situation to justify a PEx or there's enough evidence to show the PEx is justified surely. Otherwise an appeal would be possible, and any parent who sees an exclusion for no reason would surely be challenging it?
The amount of evidence we get asked for before a managed move fails is precisely because it makes it clear what the issues were should there be an appeal.
I can't speak for every school but you seem to be suggesting that schools randomly decide they can't be bothered with a student so permanently exclude a 4/5 year old for no reason and, despite there being no grounds for an exclusion, the parent just accepts this, no appeal, no question.
Oh and also @LolaSmiles a heck of a lot "legal" exclusions are also very very wrong
The difference between you and those of us in favour of keeping PEx as an option is that some of us think there are situations where PEx is absolutely reasonable, whereas you seem to repeatedly conflate a range of issues based on the fact you just don't like exclusions.
The more I read about the NME, Ban the Booths (with their regularly changing definition of booths), Pivotal, and other consultant companies, the more I see a hell of a lot of victim blaming where everyone other than the individual student is held responsible for the student's actions. There's always some excuse that means the student who has bullied, harmed, assuated, verbally abused is prioritised over the right of other students to be safe in school.