I'm always confused why people think that not having the right to live and work in the EU prevents someone from working for a european airline. You can commute to europe, work on a european contracts and aircraft as a UK national, the same is true in the other direction.
In any case, if you see BizAv in your future at all, get dual licenced between ireland and the UK, otherwise it's up to you but I'd consider that you'd be closing the door to an opportunity without it.