U can do a CAA PPL and because it is an ICAO licence, once u get back to Ireland, u can approach the IAA and ask them to issue a IAA licence against ur CAA one...then u can go down the route of doing ur commercial training in Ireland
If u stick with the CAA PPL, any further training will have to go thru the UK system
I did a CAA PPL in 2000 and went thru the UK system as the IAA were not JAR compliant at the time...But personally I wud rather go thru the CAA system as opposed to the IAA, that's just a personal thing though, don't know what others think about it