If the designated local regulatory authority considers that a certificate should be varied, suspended or cancelled on a ground specified in section 82, it must give the holder notice in writing--
(a) stating that it proposes to take that action and the ground or grounds for the proposed action; and
(b) if it proposes to vary or suspend the certificate, stating the proposed variation or period of suspension, as the case requires; and
(c) inviting the holder to respond in writing to the designated local regulatory authority within a specified period (not being less than 7 days nor more than 28 days after the notice is given) as to why the proposed action should not be taken.