Forced overtime and childcare responsibilities

[Bevplus3]

Hey, can anyone help on the topic of forced overtime for a parent with childcare responsibilities?
DH is a tradesman and gets given a list of jobs to get through in a day, and if the jobs are complex or far away from each other he ends up having to work overtime to get them finished which is a very frequent occurrence. Problem is he has 1hr 15 between finishing work and picking up DD1 from afterschool club, and in that time he needs to pick up DD2 and DD from childcare. It’s plenty of time if he finishes within 30 mins of his finish time, but bosses kick up such a fuss if he asks to leave close to finishing time to pick up kids (and recently told him if he needed to leave work on time he could just quit).
I can’t help as I work til 6pm an hour away, and he has several times been very late for pick ups and has even had to take DD1 on a job with him when it was just a drop off.
Does anyone have any idea if the company are allowed to force him to work overtime with no notice meaning he can’t pick up his kids?

That sounds about right though for trades people sadly

He could try self employed I guess

But I'd be looking into getting a childminder who would be more flexible

Does his contract say this is expected?

He could put in a flexible working request to have fixed hours but his employer could reject it if they could come up with business reasons to do so.