Die Franken? Or the Flemish? Well, they were certainly Germanic. But that is long, long ago. And anyway you speak English, and language is the dominant feature of any culture which distinguishes it from all the others. The French don’t speak German. And you have the English Queen. Normandie is not represented in the Bundestag. France and Germany are not as far apart as history has made them out to be, but to an outsider, the difference is clear. No doubt the Bretons are not Provencale, or vice-versa, and the Scottish are not Saxons, but Breton and and Provencale and Alsacien are all French, and English and Scottish are all Anglo-Saxons: common language, common country, common Queen, common government, common concepts of law (if not the same laws).
The Breton are Celts, but they’re French.
The Scottish are Celts, but they’re Anglo-Saxons.
How can you be a Celt and an Anglo-Saxon? That is just impossible. An Anglo-Saxon or Celt is a genetic difference, not one of nationality.
As for the British Monarchy, the first British Monarch was not from the English throne, but was the King of Scots. It was the Scottish King who took the English throne and united both crowns, not the other way about.
On speaking English, the Irish speak English, but they are not Anglo-Saxon either. You also speak English - does that mean you are Anglo-Saxon too?
Scotland and England have completely different legal systems, so your shared law part is wrong as well. Britain has two completely different legal systems - Scots Law and English Common Law.
We also have completely different religious and education systems.
I am sorry but because you are not sure of these things doesn’t make them any less factual.