31Variation and discharge of certain orders for relief
(1)Where the court has made an order under section 21(3) or section 22 or any of the provisions mentioned in section 29(2) of this Act (other than an order for the payment of a lump sum), the court shall have power to discharge or vary the order or to suspend any provision thereof temporarily and to revive the operation of any provision so suspended.
(2)The powers exercisable by the court under this section in relation to an order shall be exercisable also in relation to any instrument executed in pursuance of the order.
(3)In exercising the powers conferred by this section the .court shall have regard to all the circumstances of the case, including any increase or decrease in the means of either of the parties to the marriage.