7. The consumer on whom is served such notice as is mentioned in regulation 6(1) may, within the period of 21 days beginning with the date of service of the notice, or such longer period as the Secretary of State may at any time in any particular case allow, appeal to the Secretary of State against the action taken in the exercise of a power conferred by regulation 5(c) on any of the following grounds, that is to say—
(a)that the defect or other circumstances specified in the notice did not constitute a danger such as to justify the action taken specified in the notice;
(b)that the defect or other circumstances so specified did not exist at the time the action was taken; or
(c)that the defect or other circumstances so specified have ceased to exist.