“(1) If a court is satisfied that a will is so expressed that it fails to carry out the testator's intentions, in consequence— (a) of a clerical error; or (b) of a failure to understand his instructions, it may order that the will shall be rectified so as to carry out his intentions. (2) An application for an order under this section shall not, except with the permission of the court, be made after the end of the period of six months from the date on which representation with respect to the estate of the deceased is first taken out.”