The Queen's mother was full-blood British, born in Scotland. Prince Philip is Greek and Danish. Prince Charles is perhaps one-eighth German. Both Diana and Kate have long British ancestry, some of it royal, so William's children are only a squillionth German. Time to retire that old chestnut that has been a slur since Queen Victoria's time.
Don't say that to a Greek. "Schleswig-Holstein-Sonderburg-Glücksburg" isn't exactly a name like Papadopoulos. The family was Danish royalty for a much longer period, but most of Phil's ancestry was German. Some English, too, since both Phil and Liz are descended from Queen Victoria. Hence the "inbred."