See page 7 of
this Standard Life Guide:
A full encashment of the 75% balance will be subject to:
marginal rate (assuming the new employment is soaking up the lower rate band)
+ USC (very few exemptions from USC and this is not one of them)
+ PRSI (no exemption until age 66).
Interestingly, the document does not have a line item for your specific scenario - let's call it 'Taxable Cash for 75% balance' (probably because it is not that common) but effectively the tax treatment mirrors that of the line item 'ARF full encashment'.
Also, from
this Irish Life Guide:
TAX MUST BE PAID ON RETIREMENT INCOME
Retirement income is treated like normal income so income tax must be paid on it. Retirement income includes:
• Guaranteed income for life – also called an annuity.
• Withdrawals made from an Approved Retirement Fund (ARF) or an Approved Minimum Retirement Fund (AMRF).
• Withdrawals from a Vested PRSA.
• Taxable Cash Payments.
• Trivial Pension Payments.