ewww...second time posting this as pprune wouldn't let me first time!!
Anyway...
Tom,
VFR in Ireland is pretty easy.
You will need a flight plan when comming into Ireland for the first time, and when leaving as you are crossing an FIR. You will also need one if you are crossing the FIR into Northern Ireland. Will will need one whenever any part of your flight goes through controlled airspace. Other than crossing an FIR, and for controlled airspace you won't need one (unless planning long over water trips!!).
All the controlled airspace you will encounter for VFR will be Class C. I think you need a transponder to enter controlled a/s here, but not 100% sure....it changed a year or two ago. I'll check it out for you, if it's an issue.
If flying over 3000ft, we use the semi-circular rule. Tracks 000-179 = odd flight level +500. Tracks 180-359=even flight levels +500.
No VFR at night.
R/t is pretty relaxed.
If flying to Dublin, then I'd suggest Weston, rather than Dublin Int. Dublin can be quiet expensive for non based a/c, or so I'm told!
Need any info, let me know.
dp