I suspect it’s something very similar to the one played here:
That one is a flute played in the old Kilfenora fife and brass band early in the last century. The band’s instruments were destroyed when the Black & tans burned the hall where the instruments were kept but some of the flutes survived because they were small enough for the players to take home. Anyway, the one in the in the photo is in F.
Your flute looks to be somewhat earlier than 1894. I have a single-key Bb flute stamped ‘Butler, Haymarket, London’ that looks very similar. Butler also had retail premises in the same quayside area of Dublin.