The 1856 painting "The Blind Girl", by John Everett Millais

https://en.wikipedia.org/wiki/The_Blind_Girl

shows an unusually shaped square-ended concertina. Presumably the models were painted from life in the studio with background landscape later integrated, or perhaps vice versa; and the instrument held by the model would have been an actual one used as one of the props for the work. It looks like a 30-key anglo-system instrument.

Has anyone come across one of this shape before; or have any idea of its make, provenance, &c?

≈M≈