Then again, it might be because I'm mainly a contractor; I didn't try to get employed full-time.
I bet that's most of it. Can't speak for Ireland, but almost every country has a lot of extra burdens and regulations that come with "employees" vs "contractors".
It's the first time in five years I'm withouth permanent work. I think I might give it a try to do a bit of freelancing or contracting for a change.
Where does one even get started though?
Don't stop at the first "no", send a few dozen applications and see what answers you get.
This is pretty much the easiest thing you can do; I'm happy with the results because my income expectations are lower (being from Eastern Europe) than those of a native British. Meet-ups, investigating companies' needs and everything else that @patio11 describes are needed for much better results.