I agree with the idea of a uniform in general, making less of a competition over who wears what, less bullying because someone can't afford designer clothes, everyone has something to wear for the next day and it does just looks smarter. Having said, that I feel a lot of teachers get some sort of power trip about the whole thing. Focusing so much on someone wearing a jacket to and from lessons, or shoes not being the right kind of black or hair bands not being school colours is just nitpicking and takes away valuable teaching time.
Sending students home for such minor offences is just ridiculous. Education should not be disrupted because of something as trivial as what kind of footwear someone is wearing. Maybe if they used more time to focus on those who are struggling with school work than those who aren't wearing the right uniform they'd see an increase in good grades.
Also, this head teacher doesn't seem to have a care in the world that she's sent home students who have come to school in imperfect uniform not, because they want to but, because they can't afford it. If schools are going to force students to wear their clothes they ideally need to be given free, or at least made affordable, otherwise they have no right to complain when parents don't want to buy something overpriced that their child is going to easily grow out of or become out of date when the school gets a new headteacher who decides pupils need to wear a different overpriced uniform.