You will get arguments over provenance on a number of the songs- Are they "Anglia," Caledonia," or "Hibernia"? If you attribute "Black Velvet Band" to Hibernia, then you must reference an Irish version of this song which prob. orig. in England).
"Parting Glass" is Scottish; you give lyrics for an Irish derivative- but people looking for the song under Caledonian would not find it.
"Billy Barlow" originated in England (derivatives all over, including Slim Dusty's land).

I wonder if a straight alphabetical listing of UK and Ireland songs would be better? Of all songs for that matter.
Several Brasilian-Portuguese songs are listed under Hispania. They should be under Lusitania. The heading 'Iberian' would cover both.

This might seen like silly carping now, but when you get up to 1000 songs, classifications will come back to h'ant you.
(I just got Silbers' "Folksinger's Wordbook" with over 1000 songs. The index to songs has no categories, the path taken in most of these songbooks. The Silbers did put contents categories at the front of the book, but I find them not really helpful). This route might be best.