The general position under the UK/Ireland tax treaty is that tax is payable only where the beneficial owner of the interest is resdient. Assuming that you were UK resident for 2012 then you would be liable to tax in the UK with no tax liability in Ireland. You should contact your Irish bank and advise them of your UK residency and request that no DIRT (tax deducted at source by your bank on the interest) be applied to the interest. I'm sure they will ask you to prove your UK tax residency. DIRT deducted in 2012 can be reclaimed on Form IC4 which is on the Revenue website.