Yes, concertina rather than accordian. But, the point is, surely used on forebitters. And why do you not accept that it would have been irrational to expect an unaccompanied tradition, and, further, that instruments were at risk of being marginalised in the process of collection? The ability or otherwise of the few living English source singers (I'm sorry if you don't understand the difference between "folk singer" and "folksong singer" - I think it tallies well with the 1954 definition) who survived into living memory to accompany themselves, or the failure of their preferred accompanists from their youth also to survive is at best marginal evidence of what the tradition actually was.