Ah yes, the British Israelite theory. I personally don’t dispute it. Some say the British crown descends from Israel. Could be.I recently went down this rabbit hole somewhat, came across Yair Davidiy and his site https://www.britam.org
Fair warning, there is a lot of information on that site.
He doesn't seem as smart as he thinks he is. Initial point that house of Israel was used for the united 12 tribes before division means what? They were divided and had different prophetic futures spoken for them. What would he do with Jacob prophesying over Ephraim that "His seed will become a multitude of Gentiles" oh wait, the rendered it nations there. Same difference actually. Israel was told "your descendants will inherit the nations"