Mountbatten-Markles, not Windsor-Markles! If Mrs Elizabeth Mountbatten and her egregious offspring choose not to use their legal name, that's up to them. But until and unless I see a Deed Poll to that effect, the family name is Mountbatten (and the Queens' maiden name was Saxe-Coburg Gotha - not my fault is she's ashamed to own up to being half-German).