Cant see it being any different to running on southern Irish plates as long as the address is changed.
About a million years ago, i bought a Cortina 2.3s on Irish Plates and i had them changed to UK ones. No trouble at all and no expence except the price of getting a set of new plates made up. When dvla notified me of my change, i had a month to get it changed over to its "new" age related UK plates