Subject to paragraph (2), no proceedings for an offence under any of the provisions of this Order or any instrument made under it
Proceedings for an offence under any provision contained in, or having effect by virtue of, Part V, other than proceedings for an offence under Article 23(6) or proceedings by virtue of Article 25(2), shall not be instituted—
unless there has been served on the person charged notice in writing of the date and nature of the offence alleged and, where the proceedings are in respect of one or more of a number of articles of the same kind tested on the same occasion, of the results of the tests of all those articles;
except where the person charged is a street trader, unless the said notice was served before the expiration of the period of thirty days beginning with the date when evidence which the person proposing to institute the proceedings considers is sufficient to justify a prosecution for the offence came to his knowledge;
after the expiration of the period of—
twelve months beginning with the date mentioned in sub-paragraph ( a), or
three months beginning with the date mentioned in sub-paragraph ( b),
whichever first occurs.
For the purposes of paragraph (3)—
a certificate of a person who institutes proceedings for an offence mentioned in that paragraph which states that evidence came to his knowledge on a particular date shall be conclusive evidence of that fact; and
a document purporting to be a certificate of such a person and to be signed by him or on his behalf shall be presumed to be such a certificate unless the contrary is proved.