Ex-gratia payment to be taxed normally.
From IT21 leaflet:
Non-statutory redundancy payment i.e. the amount payable by your employer, which is over and above the statutory redundancy payment. The non-statutory redundancy payment is also known as a golden handshake or an ex-gratia payment (e.g. a person receives a lump sum of €20,000, which includes statutory redundancy of €5,000. Of the €20,000, €15,000 is taken into account and the €5,000 is ignored for tax purposes).