123.—(1) Without prejudice to the generality of regulation 25 and Schedule 3, but subject to paragraph (2), for the purposes of earnings-related contributions, there shall be excluded from the computation of a person’s earnings any payment in respect of employment as a mariner which is—
(a)an interim payment of earnings by way of an advance;
(b)a payment to some other person of any part of such a mariner’s earnings allocated by him to that person;
(c)a payment of a special payment while sick abroad (as defined by the National Maritime Board).
(2) Nothing in sub-paragraph (a) or (b) of paragraph (1) shall be construed as preventing any sum deducted on account of any such payment as is specified in either of those sub-paragraphs from another payment of earnings being treated as comprised in those earnings.