@Penstemmon
I hope you can see the point I was actually making, which is that somebody commented on the decline of Christianity in the UK and I pointed out that many immigrants are actually boosting the numbers of various Christian churches.
In the case of my friends (and I do think of them as friends) they're all British-born. They're not Nigerian or African or anything else. They're British. I think we need to get used to the fact that the British have all sorts of different skin colours and facial features. However much they adopt 'British' culture over the generations, they can't change their physical appearance, so I don't think calling them 'black' is an insult.
I don't know what kind of culture the children will adopt, but at the moment, their food is based on traditional Nigerian food (apart from pizzas, burgers, fish and chips, etc
). The mother works as an accountant in the City and wears a smart suit for work and usually wears jeans when not at work, etc, but she wears traditional Nigerian clothes for celebrations and weddings, etc. I've seen the photos and she looks stunning. The girls have their hair braided. The parents are very strict about bringing up their children, as many Nigerian parents are, and they're obsessed with education. They also follow a very strict form of Christianity, which I understand is common in Nigeria.
Despite all the above, they're British and I think would be insulted at being called Nigerian. Britain is made up of all sorts of different people with different cultures. There is no one form of British culture (or DNA), which is why I find this whole British values thing confused.