(1) Where a petition for divorce or for nullity of marriage has been presented, then, subject to subsection (2) proceedings under section 21, 22, 23 or 24 may be begun subject to and in accordance with rules of court, at any time after the presentation of the petition save that—
(a) an order under section 22 or 24 shall not be made unless a decree nisi of divorce or of nullity of marriage as the case may be, has been granted;
(b) without prejudice to the power to give a direction under section 33, no such order made on or after granting a decree nisi of divorce or of nullity of marriage, and no settlement made in pursuance of such an order, shall take effect unless the decree has been made absolute.
(2) Rules of court may provide, in such cases as may be prescribed by the rules—
(a) that applications for ancillary relief shall be made in the petition or answer; and
(b) that applications for ancillary relief which are not so made or are not made until after the expiration of such period following the presentation of the petition or filing of the answer as may be so prescribed, shall be made only with the leave of the court.
(3) In subsection (2) “ancillary relief” means relief under any of the following provisions of this Act, that is to say, sections 21, 22, 23 and 24.