Alan Day, you are not the first to wonder…………
I have a record by one Nigel Pickles called the Mexborough English Concertina Prize Band (out on Plant Life Records PLR 055) bought on a visit to the UK in mid 80's. The sleeve notes contain a potted history of concertina bands and the Mexborough Band in particular. He says this band was still practising with 5 members in 1978 when they decided to sell the instruments and disband.
Nigel Pickles acquired 10 of the concertinas and all the music from Willis Watson, the last band leader and his brother Archie. The recording is Nigel recreating the sound of the band by playing all the instruments – on 16 track tape.

Nfj