Personally I have an issue with both HRH The Duchess of Cambridge and HRH The Duchess of Sussex being referred to in their occupation as "Princess of the United Kingdom" - as they are only Princesses by marriage and not Princess of the United Kingdom in their own right... but Im sure others will have their own thoughts, its just my personal thoughts.
I note that Prince Harry is referred to on Archie's birth certificate as "His Royal Highness Henry Charles Albert David Duke of Sussex" - not "Prince Henry Charles Albert David, Duke of Sussex"
From what I have seen, the whole matter of what is written is a big of a "dog's dinner" - so many inconsistencies/errors etc.. and to be honest, I'm sure that the Registrar has written what they have been told to? or you would think if they had written it themselves, on such matters - you would check? knowing how much of an interest people have in these matters - after all no parent wants to see a mistake, regardless of your rank, high or low.
In response to the "Duke of London" fictional question, from what I have seen there has been a mix of name/title/surname etc etc and no set pattern. I know what I would write, but then I am a Royal nerd and like things to be done correctly. If it were left to the members of the jokers who write in the Daily Mail, Im sure that there would be a hell of a lot more errors and mash-ups of names, titles, surnames and rank etc (said with a great deal of sarcasm!)
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