G'day English Jon, "... Doesn't the concertina pre-date the accordion? Or am I mistaken? When was Wheatstone, 1830 ish? ..."Buschmann's first accordion patents, in Germany: 1821 Important improvements by Damian in Vienna: 1829 (both to what we now call melodeon / button accordeon, depending on size and layout)
Wheatstone's first patents on 'English' concertina: 1827 Important improvements on concertina; 1840
The German concertina is a German blending of Wheatstone's concertina size box with a split right hand end of an accordion. the Anglo-chromatic is that with added row(s) of semitones OR alternate direction notes.
Regards,
Bob Bolton