Chris, yes it's x49113, serial 450. Zonophone Twin, the green label. It says English Concertina, not duet on it. It's not cracked or scratched but would need cleaning up.

BTW I'm not running, just supporting.

Alan, I don't think I have any group concertina 78s but I'll be going through them next week and I'll keep this in mind. I have plenty of Wyper Bros but that's melodeon.