21.—(1) This paragraph applies where two persons—
(a)have gone through a marriage ceremony with each other outside the United Kingdom; but
(b)are not, or are unable to prove that they are, validly married to each other for the purposes of the law of Northern Ireland.
(2) Where paragraph (1) applies, any registrar may, on an application made to him by those persons, solemnise their marriage as if they had not already gone through a marriage ceremony with each other.
(3) A registrar shall not solemnise a marriage under paragraph (2) without the approval of the Registrar General.
(4) Articles 3 to 7 and 18 to 20 shall apply for the purpose of solemnising a marriage under this Article with such modifications as may be prescribed.