When you make your return for the year in question, the tax calc will give you credit for any tax deducted at source by Irish Life, details of which will be returned directly to Revenue anyway.
What type of tax is being deducted I don't know so if its not a Capital tax then maybe not
Profits on Life Assurance based investments are not subject to CGT. Any growth on the fund is taxed at source under "exit tax" rules. You then have no further tax liability. However you cannot offset any such exit tax against either your CGT exemption limit or against any other investment losses.