Yeah, like London is 45% ethnic, but the whole country is only around 12% ethnic. Even in the cities, Somalis tend to cluster in specific boroughs and towns. You would be surprised at the number of London Boroughs with little or no Somalis.
BTW, There is almost half a million Romanians in the UK. There is nearly a million people born in Poland who live in the UK. I don’t even know why racists complain about Eastern Europeans. Almost 200k Poles settled in the UK in the 20th century and all of them are now White British. The grandchildren of todays Poles will also be white British. Somalis will become low class black British in a few generations.