30.—(1) For the purposes of section 146(1) of the Social Security and Contributions and Benefits Act, a Crown servant posted overseas shall be treated as being in Great Britain.
(2) A Crown servant posted overseas is a person performing overseas (but not in Northern Ireland) the duties of any office or employment under the Crown in right of the United Kingdom—
(a)who is, or was, immediately prior to his posting or his first of consecutive postings, ordinarily resident in the United Kingdom; or
(b)who, immediately prior to his posting or his first of consecutive postings, was in the United Kingdom in connection with that posting.