Can so too. The honours system recognises service to the state and crown, and some of the more modern honours have political and geographical restrictions to the State, the Commonwealth, the Empire, and so forth, but knighthoods are too ancient for that sort of thing.
Okay, I am on shaky ground as the Monarch may have technical rights that are not exercised, and may not work any longer. She may dissolve parliament, but she is unlikely to get away with it unless they have been really, really unconstitutional and naughty. But she could probably make someone a knight wherever they were, and if they accepted, then a knight they would be for most of us. You could try telling the Lady in the Shiny Hat that she can’t do that. She can’t order beheadings either, but no point in pushing your luck, and some of her knights still carry spiky stuff.
Ain’t gonna happen anyhow, but one can dream…
