Hi Stephen, Thanks for your reply. From the serial numbers quoted in John Constable's thread, it looks like about 865 Lachenal concertinas were made each year between 1910 and 1926, so mine is probably about eleven months older than yours, ie early 1925. One of the reeds always sounds and there are a few leaks in the bellows. I will purchase a copy of David Elliott's book before I take the ends off. It looks as though these posts should be in John Constable's thread - is there a moderator who could do this?
Best wishes and thanks