Any income, including pensions, is subject to tax under the PAYE regime (deducted at source), but how much you pay (if any) depends on where you are in the tax bands at the time. Impossible to predict, I feel. Don't rely on guesswork.
Whether or not you are entitled to State Pension depends on a number of factors, including the type of stamp you paid, and your stamp payment record, as well as whether or not your DB scheme (occupational?) is integrated with the State Pension (refer to scheme rules). Phone Social Welfare on 071 915 7100 (Sligo) re state pension entitlement. More likely to get through earlier or later in the day.
You may have a number of options re AVC's - speak to a qualified financial advisor, don't rely on non-verifiable sources of advice, also re further avc contributions.