25.—(1) Proceedings for an offence under regulation 19, 20, 21, 22, 23(1) or 24 may be brought within a period of 6 months from the date on which the procurator fiscal first knows of evidence sufficient, in the procurator fiscal's opinion, to justify proceedings.
(2) But no such proceedings may be brought more than 12 months from the commission of the offence.
(3) For the purposes of paragraph (1)—
(a)a certificate signed by or on behalf of the procurator fiscal and stating the date on which the procurator fiscal first knew of evidence sufficient to justify the proceedings is conclusive evidence of that fact; and
(b)a certificate stating that matter and purporting to be so signed is deemed to be so signed unless the contrary is proved.