@Uricon2 I totally agree.
I've known of Traveller boys in particular being deprived of the most basic education because of being kept out of school to help their fathers. The result is that their literacy level is that of a 5 yr old.
The lack of supervision from the powers that be doesn't really help - once the parents notify the LA that a boy is being "home educated", then that's often the end of it. (The same holds true for a "home educated" pupil from any community, in my experience.)
Apart from those whose fathers had established settled businesses in the area, the boys tended to disappear a year before they were due to take qualifications.
There was one case where a "settled" boy disappeared a year early. We had kept reporting that he was hitting girls in his year group. The school authorities had had a feeble response to the matter.
I got into work one day to discover that the boy had left permanently. The girls in his year group gleefully shared the story of how how he'd "battered" a girl and had been astonished when a girl in the year above had taken justice into her own hands. Apparently, he could handle the shame of being "a lassie basher", but not the shame of being "battered" by a lassie.
The father had quite a lucrative business, so I expect that the boy was put to work there.
For most, it's a case of still being on the roll but being taken out for months at a time. In one notable case, the boys told us that they'd been in Ireland. "Oh, did you fly or get the ferry?"
"No, we drove..."
"But you would have had to take the ferry then?"
"No. We all went to sleep in the van and our dad drove us to Ireland..."
In my experience, the girls tend to stay in school for longer, but are often deprived of the chance to get the qualifications that they're capable of taking because of being taken out of school at exam time, etc. (This phenomenon isn't unique to the Traveller community, I have to say, but it's more prevalent.)
As I think I mentioned above, the timing of Appleby Fair is particularly problematic - the Scottish exam diet normally stretches from the end of April to Early June and Traveller families often hit the road well in advance of Appleby. If a child is enrolled for an exam and misses it without mitigating circumstances, then that's an end to it.
There is absolutely no doubt that children who could have done really well academically have been deprived of the opportunity to receive good grades.
The sexism within the Roma community (again, in my experience) takes on a different form. It's the girls who are enrolled but then taken out of school to act as childminders or - in one case that I'm aware of - to be taken to another town to beg.
I had one Roma girl in my class who was particularly bright. She was a polyglot and she and her father were keen for her to go to university. However, she told me that her father's friends kept mocking him for having this ambition for her and I don't know whether she made it or not - latterly, she had started to truant along with a couple of the Roma girls whose fathers were less supportive of a formal education.
It may well be that most children are content only to have a secondary education, but it's a great pity that cultural prejudice can prevent children from taking another path that they might wish to follow.
I include my own family in that. I have a distant cousin on my dad's side who - like me - had an Eastern European dad and a Scottish mother. His daughter was offered a place at uni. My cousin's wife (a Scottish Fifer) informed me that their daughter was most certainly not not going to university: "I would just be working to put her through university and what's the point of that?"
I doubt that she'd have said the same of her son - but then, he didn't show the same academic promise as the daughter.
NB The university was a Scottish one, so there would have been no fees to pay.