6.—(1) A person who has prepared a safety case pursuant to these Regulations shall revise its contents whenever it is appropriate; but nothing in this paragraph shall require the revision to be sent to another person.
(2) Where a revision proposed to be made under paragraph (1) will render the safety case materially different from the last version sent to the person who accepted it pursuant to these Regulations, the revision shall not be made—
(a)unless the revision has been sent to that person;
(b)unless that person has accepted the revision or (where he is an infrastructure controller) has notified the person who prepared the safety case that the revision does not affect and is not likely to affect the performance of the health and safety duties of the infrastructure controller; and
(c)where the person who accepted the safety case is an infrastructure controller, until 28 days after the revision has been accepted or until 28 days after a notification has been made under sub-paragraph (b),
and where the revision is to a safety case accepted pursuant to paragraph (ii) of regulation 5(1)(b) the Executive shall, before accepting the revision, take account of any views given to it by the relevant infrastructure controller referred to in that paragraph as respects the matters referred to in that paragraph.
(3) A person who has prepared a safety case which has been accepted pursuant to these Regulations shall make a thorough review of its contents at least every three years.