Ah, thanks, I see. But they are already separate countries, not regions. It's a state divided into countries already, which in itself recognises that ethnic diversity.
Depends a bit how you define country. Scotland wasn't able to stay in the EU for example. A country would be able to do that, I think.
Plenty of federal and quasi-federal countries have tensions between their constituent states, and separatist movements. The UK isn't a proper federal system, of course, but much the same principle applies.
It's borrowing the language typically used in the media to describe Middle Eastern ethnic conflicts to a European ethnic conflict. The same way it describes the U.K. as an "Oil Rich Kingdom" (which it is, of course).
Administratively, Scotland is less of a country than, say, the British Virgin Islands. While it has a Parliament and separate legal system the list of independent competences is much smaller.