There have been people of West African descent in England since the early medieval period.

So? Look, I'm aware that there has been a recent drive to erase British history with this overt (and often comically historically inaccurate) diversity agenda (see: Netflix slop and BBC docudramas), but I'm genuinely not aware of any person who would consider West Africans to be "native Brits" (in the ethnic sense of the term, of course). To a reasonable common man, it's absurd.

Even if this is your view, it's clearly not the view of the original author so by introducing this fringe opinion you're only serving to confuse the discussion.

How can you possibly define "native Brit" in a way that includes, say, Saxons, but excludes West Africans who immigrated in the 1200s, without simply saying "people with light skin"? Or is 1066 your cutoff? Why?