3.—(1) The Secretary of State may by notice in writing to the persons responsible for the management of a museum—
(a)vary the conditions specified in a licence held in respect of the museum; or
(b)vary the licence so as to extend or restrict the premises to which it applies.
(2) For the purposes of sub-paragraph (1) the Secretary of State may by notice under that sub-paragraph require the persons in question to produce the licence to him within 21 days from the date of the notice.
(3) The Secretary of State may by notice in writing to the persons responsible for the management of a museum revoke a licence held in respect of the museum if—
(a)at any time he is satisfied that the continuation of the exemption conferred by the licence would result in danger to public safety or to the peace; or
(b)those persons or any of them or any employee of theirs has been convicted of an offence under this Schedule; or
(c)those persons have failed to comply with a notice under this paragraph requiring them to produce the licence.
(4) Where a licence is revoked the Secretary of State shall by notice in writing require the persons responsible for the management of the museum in question to surrender the licence to him.