I live in a multicultural area in London where maybe 50% of the people are white. Our local school is mainly non-white. In DS's class there is about 5 white children and about 21 non-white children.
The school has a good rep and twice was in the OFSTED top 300 schools in the country. Why do you think it's not representative of the neighbourhood. The other schools around have very strict catchment areas so I don't know where they go to school.