"Can someone explain to me the tax relief on mortgage repayments. Are repayments made before or after tax?"
Rediculously, both systems are in use! It depends on which mortgage lender you are with. One does not get a tax-relief on mortgage Interest anymore. A new system called TRS applies to Mortgage Interest on home loans. The TRS (Tax Relief at Source) is a credit. As its name suggests it is supposed to be at source. Lenders who are, or were, building societies, apply the TRS credit at source. These include EBS, Irish Nationwide, Permanent tsb (previously Ir. Permanent Building Society) and First Active (previously First National Building Society). The lender will advise you of the gross payment less the TRS to arrive at the Net Payment you need to pay. They will diduct the Net Payment from your account. The 'Clearing Banks', including ICS Building Society (owned by Bank of Ireland) requested abstention from the 'at source' rule. They deduct from your account the higher gross amount and then re-imburse you with the TRS Credit to your bank account. In some cases they are crediting the account of a person who used to pay the mortgage even though the other party to the mortgage now pays the mortgage.
THE TRS is not a tax Credit. It is a credit on the home loan. A person who's circumstances have changed is in receipt of a Social Welfare may also get the TRS credit.