Should have said 'popular in Ireland'; just like those Soodlums Irish songbooks do. In its current form 'Willa fjord' is a Shetland tune and its rhythm makes it distinctly so, but you may need to look east to Europe/Scandinavia for its origins (maybe likewise 'St Anne's Reel is of European origin? Yes I know it's 'written' by a named person, but if you know anything about traditional music you'll know that means very little.
I heard Tom Anderson play this many times and whenI hear categoric statements of fact' like 'they are not very similar' I would suggest such total dismissal lacks perspective- open your ears and listen again - the partial similarities between many reels is striking, and these two particularly so- syncopation has nothing to do with it.