24.—(1) In addition to the other occasions on which a duty holder shall revise a current safety case pursuant to these Regulations, a duty holder shall revise a current safety case—
(a)when appropriate; and
(b)when directed to do so by the competent authority pursuant to regulation 25(1).
(2) Revisions made under paragraph (1)(a) which make a material change to the current safety case are not effective unless—
(a)the duty holder has sent a version of the current safety case which incorporates the proposed revisions, showing clearly where they are to be made, to the competent authority—
(i)at least three months, or such shorter period as the competent authority may specify; or
(ii)where the revisions relate to a combined operation, at least six weeks, or such shorter period as the competent authority may specify,
before the revisions are to be made; and
(b)the competent authority has accepted the revisions.
(3) Without prejudice to the generality of paragraph (2)—
(a)no well operation constitutes a material change;
(b)the movement of a production installation to a new location to be operated there constitutes a material change; and
(c)the conversion of a production installation to enable it to be operated as a non-production installation constitutes a material change,
to the current safety case for the purposes of paragraph (2).
(4) For the purposes of paragraph (1), it is to be regarded as appropriate to revise a safety case in respect of a material change to an installation.