320.—(1) Anything published in accordance with a provision of this Part (other than regulation 319 (“a publication”) must specify the date on which it is to take effect.
(2) The Ministers must give notice of the date mentioned in paragraph (1) by notices published in the London, Edinburgh and Belfast Gazettes not less than 21 days before that date.
(3) Where in any proceedings an enforcement authority produces a copy of a publication, it shall be presumed that the copy is a true copy of the edition of that publication that was in force at the time when the events that are the subject of the proceedings took place, unless evidence is adduced to the contrary.