I'd just like to mention that anybody of the appropriate generation is likely to have at least one mixed race friend; and the key thing is that Peter Grant's mother is from Sierra Leone rather than the West Indies, which is much more common and very different in many ways. One would have to specifically ask someone who had one parent from West Africa.

Apart from that, there is a great deal in common between people from any minority*, and also between people growing up between two cultures.

*With exceptions. See Mama Thames' comments on there being too many Igbos (also from Nigeria) around.