4.—(1) A person shall be treated for the purposes of paragraph 1 above as having been ordinarily resident in the British Islands throughout the three years preceding the relevant date if he is a British citizen within the meaning of the British Nationality Act 1981 (1) and—
(a)he was not so resident only because he was ordinarily resident for the purposes of employment in the European Community during every part of that period in which he was not ordinarily resident in the British Islands; or
(b)(i)he was not so resident throughout that period only because his parent is such a person as is mentioned in sub-paragraph (a), and
(ii)his parent is ordinarily resident in Great Britain on the relevant day.
(2) In sub-paragraph (1) above “parent” includes a guardian and any other person having actual custody of a minor, and “relevant day” means—
(i)where the person had entered the United Kingdom before the day one month earlier than that of the beginning of the term in which he commences his course, that day;
(ii)where he had not so entered the United Kingdom, the day of the beginning of that term.