Almost all the prohibited areas up north have been removed with the exception of a remaining few above prisons. The south armagh one is no more. UK AIP has info and it may still be NOTAMed, although it's been a while since the change.
One thing to watch for when flying down south as compared to the UK is, 'major' irish airports are class C airspace and will require a flight plan for all movements. This includes Dublin, Weston, Waterford, Cork, Kerry, Shannon, Galway, Knock, Sligo, Donegal. The remainder don't require flight plans. You may get away with calling up before the zone boundary, but don't count on it.