"Where, within two years of death (or such longer period as the Revenue Commissioners may allow) the disposition of a property under a will or intestacy is varied by a deed of family arrangement or similar instrument, the deed is deemed to have retroactive effect from the date of death." - "The provision allowing the Revenue Commissioners to extend the period beyond two years is to cater for cases in which it is not possible for the beneficiaries to complete a deed of family arrangement within two years of death.This would occur for example where there is delay due to difficulty of proving title or where there is a large family with some members living abroad."