11.—(1) A person who has made a claim may amend it at any time by notice in writing received at an appropriate office before a determination has been made on the claim, and any claim so amended may be treated as if it had been so amended in the first instance.
(2) A person who has made a claim may withdraw it at any time before a determination has been made on it, by notice to an appropriate office and any such notice of withdrawal shall have effect when it is received.
(3) The date on which the claim is made shall be—
(a)in the case of a claim which meets the requirements of regulation 10(1), the date on which it is received at an appropriate office; or
(b)in the case of a claim treated under regulation 10(3) as having been duly made, the date on which the claim was received in an appropriate office in the first place.
(4) Where the applicant proves there was good cause throughout the period from the expiry of the 28 days specified in regulation 10(1), for failure to claim the bonus within the specified time, the time for claiming the bonus shall be extended to the date on which the claim is made or to a period of 6 months, whichever is the shorter period.