G'day curmudgeon,

I have Aat home) a c. 1930 Wheatstone catalogue which offers five different pitches for their concertinas. Offhand, I think it is something like:
Old Philharmonic,
New Philharmonic,
Continental Philharmonic,
British Philharmonic,
and
"common pitch".

The first 4 are different regional standards and the last, only for their cheapest instruments, meant it was in tune with itself, but not accrately pitched to any standard.

I believe the old British Philharmonic had A = 454 Hz, something like a quarter tone sharp of modern pitch. It is common to find old concertinas still in "old high pitch".

Retuning, by a competent concertina repairer, can be a bit tricky, because a small amount of material needs to be removed from the lower body of the reed to bring its pitch down ... and this can also lead to a loss of 'brilliance' or 'voicing' characteristics.

Regards,

Bob Bolton