(a) An individual and his or her civil partner who are living together, may, for a year of assessment, by notice in writing given to the inspector on or before 1 April in the year following that year of assessment, jointly nominate which of them is to be the nominated civil partner for the purposes of this Chapter.
(b) If the notice under paragraph (a) is not given on or before the date mentioned in that paragraph, the Revenue Commissioners shall deem one of the civil partners to be the nominated civil partner.
(2) Subject to this section, the amount of capital gains tax on chargeable gains accruing to civil partners in a year of assessment or part of a year of assessment during which they are living together shall be assessed and charged on the civil partner who is the nominated civil partner and not otherwise; but this subsection shall not affect the amount of capital gains tax chargeable on the nominated civil partner apart from this subsection or result in the additional amount
…