Yes, it was Bert himself who played concertina on Lord Franklin. I seem to remember, although I am not certain - it was a long time ago - that it was a 48 key lachenal. It was John Renbourn who "joined me on stage". It was at the Stanford in Brighton if I remember. We almost certainly did "Lord Franklin" on that gig. John played guitar and sang, I played concertina. We did that at various gigs over the years, this may be a possible cause of confusion, but, yes, it was definitely Bert who played on that track on that album.