66.—(1) The prescribed period for the purposes of section 89A(3)(a) and (5)(a) is thirty one months beginning with—
(a)where there is no declared priority date, the date of filing of the application;
(b)where there is a declared priority date, that date.
(2) But where the applicant has been notified under rule 69(5), the period prescribed for the purposes of section 89A(3)(a) and (5)(a) is three months beginning with the date of the notification.
(3) Where an international application for a patent (UK) has begun the national phase, a request for permission to make a late declaration may be made under section 5(2B) before the end of the period of one month beginning with the date the national phase of the application begins.