20.—(1) The regulator may vary an environmental permit on the application of the operator or on its own initiative.
(2) But a variation made under paragraph (1) must not reduce the extent of the site of a regulated facility.
(3) Paragraph (2) does not apply to Part B installations.
(4) Part 1 (grant, variation, transfer and surrender of environmental permits) of Schedule 5 applies in relation to an application to vary an environmental permit or a proposal to vary an environmental permit on the initiative of the regulator under paragraph (1).