Giles, I think many people feel it hides more inequalities than would be visible without uniform, it may be impossible to hide disparity in wealth altogether.
Math: I don't think in the U.K most people would make judgments about a school based on its ethnic diversity, the U.K is generally very tolerant and integrated in these respects, it certainly isn't pandered to by the use of uniform, which as you will notice has the support of the overwhelming majority of parents on this thread. I've said before that because of this backing most schools will implement a uniform and have rules about it. This also leads to a cultural difference between the U.K and the United States in that value judgments will be made about the quality of a school based on the presentation of its students.
I agree that uniform, if it is implemented and we have to have it, should be cheap, easy and comfortable. I won't change that position.
Your second post conflates sexism with practicality and the need to manage students distractions in class.
"Subtle' (makeup) expresses a value judgement about women's appearance no matter what way you cut it. The value judgement is composed of elements of misogyny and elements of class discrimination. As I said before, the idea behind it is that only slappers trowel on their makeup."
This is making too much of an argument about something that is done in order for there to be a compromise between school and students. "Subtle" is intended to discourage the wearing of excessive make up and the subsequent distractions it causes from learning in school. You have said before " my children's school" but many, many teachers would tell you the distractions that applying make up in class, or the need to stop between lessons in order to top it up cause. It also causes distractions because SOME parents police this themselves, where as others do not, this can lead to exchanges of it in school while one girl applies stuff she isn't allowed to at home. Again causing distractions from the task in hand, much in the way mobile phones do too.
The problem with rules is that while the vast majority of students would make sensible decisions, others need guidance within it, the idea that this is a misoginistic idea is piffle, and mainly used by you to make yet another attack on the British school system.
In another post you mentioned something about: "The American gpa system and refusal to acknowledge a class structure helps enormously to keep students focused and optimistic." Which could only be posted by someone who has a fundamental lack of understanding regarding the massive inequalities in the U.S education system, which produces far better results in terms of funding and learning outcomes in those from wealthy school districts whilst excluding those from outside them. The Robert Putnam study into this discussed it as a form of wealth apartheid that is going on in the US, so please do not choose to "educate" me regarding the superiority of the American education system.
You also post: "Or you can expect your student to get with the programme because ultimately it is their report card and attendance record that is at stake and they are responsible for prioritising and time management. " Which again doesn't get the fact that U.K teachers are judged by the performance of their results and in many cases are not allowed to give the excuse that X, Y and Z did not take charge of their own learning, they will then be asked:" What steps did you take to counter that?" So rules are put in place to minimise disraction etc etc.
You post about schools encouraging individuality, most U.K schools do too, but does individuality have to about your image, about what you wear? Because you then start to contradict yourself when you talk about girls receiving the idea that what they wear is what they are judged on, doesn't it.