18.—(1) If a person who is a member of the special negotiating body, or who is an employees' representative or an employee for whom there is no such representative, believes that the special negotiating body has taken a decision referred to in regulation 16 or 17 and—
(a)that the decision was not taken by the majority required by regulation 16 or 17, as the case may be, or
(b)that the special negotiating body failed to publish the decision in accordance with regulation 16(4),
the person may present a complaint to the CAC within 21 days after the date on which the special negotiating body published their decision in accordance with regulation 16(4) or, if they have not done so, the date by which they should have so published their decision.
(2) Where the CAC finds the complaint well-founded, it must make a declaration that the decision was not taken properly and that it is of no effect.