(Apparent) Rule No. 293 of Regency Writing

Do not refer to your male protagonists by their first names. They are always Mr. X. Never Mr. (name) X. Just Mr. X.

EXCEPTION: If the hero has only one name, being an orphan brought home by your father when you wanted a fiddle, then it is acceptable to call him by whatever that one name is.

COROLLARY: If, in fact, you give your male protagonist a first name along the lines of "Fitzwilliam", perhaps it is better after all to refer to them as Mr. X.*

*Not meant to offend individuals with the first name Fitzwilliam.