Read a historical novel recently, set in the time when the Saxons, the 'English,' were coming down the Rhine and settling in 'Britain.' The 'Britons,' of Celtic stock, didn't like them much and were moving out, between battles, toward Wales and Scotland. The titles are the authors', not mine.
And I always thought the Scots were an Irish tribe who settled in the lands of the Picts.
If this is all true, I suppose it only matters to pedants what you call them/us. Just call in good time for dinner.