On the receipt, it states "English Concertina" - maybe he made a mistake! How can I be sure?
An ANGLO concertina has buttons in rows. Typically 2 or 3 per side, with generally 5 buttons per row. They also have a wide palm rest with a strap the width of that rest.
ENGLISH concertinas have buttons in 4 columns per side, and only a short thumb strap and metal finger rest on each side.
Finally, when you press a button and open the bellows, then push the bellows together, while holding the same button, if you get the same tone it's ENGLISH. If different, it's ANGLO.
There are other complecations in identification, but in your case, the pics are an ANGLO.
Thanks very much for the description. This is definitely an ANGLO concertina