180.—(1) Where, after the service of a copy of a hazardous substances contravention notice, hazardous substances consent is granted for the presence of a hazardous substance on, over or under the land to which the notice relates, the notice shall cease to have effect so far as inconsistent with that consent.
(3) The fact that a hazardous substances contravention notice has wholly or partly ceased to have effect by virtue of this section shall not affect the liability of any person for an offence in respect of a previous failure to comply, or secure compliance, with the notice.