OK. The original OP asked about the child being the only one of a different race in their classroom.
Now we’d all love to believe it makes no difference but in reality it can. Being the ‘only’ black kid, the only boy, whatever, can be a bit uncomfortable.
Now when you are in a private school, there has already been a weeding out process of sorts, because it costs money to go. As such, being the only BME kid in the room is less important, because you’ve already got something more important in common with the other kids in your class. Money.
BME kids don’t exist to enlighten the white children on other cultures, BTW 