no. I just entered over 18 concertina,there are no stipulations as far as I am aware,about what kind of concertina should be played.
Madeline o Dowd was an all ireland champion, concertina player,who played the English.
However I suspect that generally the scales are weighted in favour of the Anglo rather than the Duet or the English.
I have thought about entering under Rogha gleas [assorted],but Iam not too bothered about winning,more concerned about getting constructive criticism from adjudicators,and enlightening people that the English can be played well for Irish Music..
my personal opinion is that it is equally good for jigs,hornpipes ,slipjigs, polkas, slides,more difficult for reels ,but better for airs.
having said all this,it is really the player rather than the instrument that is important.
John Clifford used to play with alot of drive on his Piano Accordion when playing Sliabh Luchra Music,although he had started on button box and later changed to Piano Accordion .