Gardiner Houlgate, the well-known West Country auctioneers, are holding a sale on Thursday 13th March, of miscellaneous musical instruments, including several concertinas, Here is the link to the catalogue page with the concertinas. The concertinas appear lower down on the catalogue page.
http://gardinerhoulgate.co.uk/Catalogues/mi130314/page004.html
Of the 8 concertinas for sale there are two concertinas for sale whose maker's names I have not come across before. One is a metal-ended anglo stamped R Carr, maker, complete with a rather worn hexagonal leather case,
Chris