23.—(1) A notice under section 59(1) that any amount payable in accordance with a schedule of contributions has not been paid on or before the due date—
(a)must be given to the Authority before the end of the period of 30 days beginning with that date; and
(b)subject to paragraph (2), must be given to the members before the end of the period of 90 days beginning with that date.
(2) No notice need be given under paragraph (1)(b) if payment has been made before the end of the period of 60 days beginning with the due date.
(3) Where a schedule of contributions provides for payments to be made by any date or within a period after that date, for the purposes of paragraphs (1) and (2) the due date shall be taken to be the last day of that period.