I play a bit of the English concertina.
This instrument was invented by a well known physist
Sir Charles Wheatstone in the 19th Century.
This particular one is made in the early 50's
just before the Boosy & Hawks buyout.

Older Lachenal 48 button treble.
Lachenal was an employee at Wheatstone factory.
He spun out and set up his own farm.

Although the metal fretwork on the instrument says "concertina",
this is not a kind of the concertina you and I know.
This one is a close kin to the bandoneon played in a Tango band.
It is a bit smaller than a bandoneon and called the Chemnitzer.
In fact it is made in Chemnitz, Germany. These are often played
in Polka bands in north America.
It is a beautifully made instrument with a weird note assignment to the buttons.