So far as I know, go to a local school with the right approvals, training as required, and an SEP AoC to get your SEP back.
For your instructor rating, I *think* if you've not been using it in that form, you'll need to do a 2-day seminar, training as required, then an FIC AOC.
I can't think of any reason this has to be in Ireland, any EASA school should do, they just need to file the paperwork with IAA.
Worth dropping an email to IAA in Dublin, they're generally really quick and responsive on this sort of thing.
G