I’ve never really like mistaken identity movies. They make you want to shout, Oh C’mon.
Historically, there were many "PRETENDERS TO THE THRONE" all over European and UK nations back then, with some people actually backing them until the final denoucement. There is quite a few interesting books about this. And, there is some whacko man, from Australia, I think, who claims to be either the late Queen Elizabeth II's some, or King Charles'...I forget which, right now, in this present day, which of course is also a FRAUD!