a song for Ireland was written by Phil Colclough,I am not sure I would like to hear Susan Boyle sing it.
She should sing that which she enjoys,which seems to be what we have heard so far,it is as silly as asking a singer of folk songs,to sing opera,or jazz,or Barry Manilow.
having heard Peter Pears[a good classical singer]murder the Water is Wide,I am not sure Susan Boyle would make a good a job of Song for Ireland
Sean Cannon does a supreerb version,but Sean Cannon,is someone who is immersed in the Irish tradition,anmd who clearly relates to the song.