13Where it appears to the Secretary of State for Employment and Productivity or the Race Relations Board on receiving a complaint to which section 16 of this Act applies or on the reference to the Secretary of State of such a complaint by a conciliation committee, that the complaint may relate to an act done in breach of a relevant assurance, then, notwithstanding anything in the foregoing provisions of this Schedule, the Secretary of State shall refer the complaint to the Board, or, as the case may be, the Board shall retain the complaint, for investigation in accordance with paragraph 14 below.