Brian, YES...I agree of course concerning the possibility to get ( firstly) the single note rhythmical effect from Anglo-playing by using the English in a similar way. "All" you have to do is reversing the bellows likewise.All the notes are there. There is a number of English-players doing trad "Irish" music this way. BUT it is a lot more demanding doing energetic and loud multi note Morris style Anglo-playing using an English likewise.

AA as an example - from decades of intensive prof practise likely got unusual strength and thus means to get along pretty well ( but I would not be surprised if he begins suffering from arthrosis in his thumb joints by now...). Anyway ...everyone ( AA too...) would be able to do it easier using an Anglo/Duet handstrap with the English rather than the unstable thumbstrap/fingerplate arrangement.

YES...I also believe the "trad Irish Anglo idiom originates simply from availability of "cheap anglo concertinas" which in reality to a great part were "cheap german concertinas" marketed in Ireland.