I've discounted Michael Fowler mentioned in Jackson's (a jug, 1757) as he worked mid 18th century and used M.F rather than MF and it's highly unlikely he was still around as a working silversmith in 1817-1824.
In Irish Georgian Silver, Douglas Bennett mentions a Michael Flanagan, 20 Dorset Street, who registered with the Company of Goldsmiths in 1813 but no registered mark is shown for him so he may have just been a jeweller. He isn't listed in Wilson's 1820 Directory, which is available online. I can't trace anyone else with the initials MF.
Although I'm sure talented silversmiths could turn their hands to making almost anything, box making was rather specialised so it's puzzling to come across a snuff box by an unknown maker.
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