17.—(1) The enforcing authority may at any time vary the conditions of a permit and shall do so if it appears to the enforcing authority at that time, whether as a result of a review under regulation 15, a notification under regulation 13 or 16 or otherwise, that regulations 11 and 12 require conditions to be included which are different from the subsisting conditions.
(2) An operator of an installation or mobile plant which is permitted under these Regulations may apply to the enforcing authority for the variation of the conditions of his permit.
(3) An application under paragraph (2) shall be made in accordance with paragraph 1 of Part 1 of Schedule 7 and shall be accompanied by any fee prescribed in respect of the application under regulation 22; and paragraphs 2 and 3 of Part 1 of Schedule 7 shall have effect with respect to such applications.
(4) Where an application is duly made to the enforcing authority under paragraph (2), the enforcing authority shall determine, in accordance with regulations 11 and 12, whether to vary the conditions of the permit.
(5) Where the enforcing authority decides to vary the conditions of the permit, whether on an application under paragraph (2) or otherwise, it shall serve a notice in writing on the operator (a “variation notice”) specifying the variations of the conditions of the permit and the date or dates on which the variations are to take effect and, unless the notice is withdrawn, the variations specified in the notice shall take effect on the date or dates so specified.
(6) A variation notice served under paragraph (5) shall, unless served for the purpose of determining an application under paragraph (2), require the operator to pay, within such period as may be specified in the notice, any fee prescribed in respect of the variation notice under regulation 22.
(7) Where the enforcing authority decides on an application under paragraph (2) not to vary the conditions of the permit, it shall give notice of its decision to the operator in writing.
(8) Part 2 of Schedule 7 shall have effect in relation to the determination of applications under paragraph (2) and the issuing of variation notices.
(9) Parts 1 and 2 of Schedule 7 shall have effect subject to Part 3 of that Schedule (national security and confidential information).
(10) This regulation and Schedule 7 apply to the variation of any provision other than a condition which is contained in a permit as they apply to the variation of a condition.