7.—(1) A structure to which the circumstances set out at regulation 5(a) apply shall cease to be an exempt structure if–
(a)any requirement of a notice under regulation 8(1) is not complied with within the period stated in the notice;
(b)it is substantially enlarged; or
(c)it is substantially reconstructed, unless, in the opinion of SEPA, which opinion shall be notified in writing to the person concerned, the risks of pollution will be reduced by such works.
(2) Any reference in paragraph (1) to the period stated in a notice is to that period as extended if it has been extended under regulation 8(5) or by virtue of regulation 9(5) or (6) and any reference in that paragraph to a requirement of a notice is to that requirement as modified if it has been modified under regulation 8(5) or by virtue of regulation 9(5).