I would say that there are a lot of people in northern France who do pass as English or even British, there are borrebies, Keltids, Atlantids, paleo...
I heard there is also some Portuguese ancestry among white south Africans (remains of the Portuguese presence in there, before British and Dutch came...
There s not even a Welsh reference in K13. His ancestry just averages closest to SE English here. Someone from Kent could get exactly the same result...