Proceedings for an offence under regulation 7 may, subject to paragraph (2) below, be commenced within the period of six months from the date on which evidence sufficient in the opinion of the prosecutor to warrant proceedings comes to the knowledge of the prosecutor.

No such proceedings shall be commenced by virtue of this regulation more than three years after the commission of the offence.

For the purpose of this regulation, a certificate signed by or on behalf of the prosecutor and stating the date on which evidence sufficient to warrant the proceedings came to the knowledge of the prosecutor shall be conclusive evidence of that fact.

A certificate stating that matter and purporting to be so signed shall be deemed to be so signed unless the contrary is proved.