58.—(1) Subject to the provisions of this Article, in any prosecution for an offence under this Order or any regulations made under it, being an offence consisting of selling, or offering, exposing or advertising for sale, or having in possession for the purpose of sale, any article or substance, it shall be a defence for the defendant to prove—
(a)that he purchased it as being an article or substance which could lawfully be sold or otherwise dealt with as mentioned above, or, as the case may be, could lawfully be so sold or dealt with under the name or description or for the purpose under or for which he sold or dealt with it, and with a written warranty to that effect; and
(b)that he had no reason to believe at the time of the commission of the alleged offence that it was otherwise; and
(c)that it was then in the same state as when he purchased it.
(2) A warranty shall be a defence in a prosecution under this Order or any regulations made under it only if—
(a)the defendant—
(i)has, within seven days, or such longer period as the court may allow, of the service of the summons, sent to the prosecutor a copy of the warranty with a notice stating that he intends to rely on it and specifying the name and address of the person from whom he received it; and
(ii)has also sent a like notice of his intention to that person; and
(b)where the warranty was given by a person resident outside the United Kingdom the defendant proves that he had taken reasonable steps to ascertain, and did in fact believe in, the accuracy of the statement contained in the warranty; and
(c)where the prosecution is in respect of a sample of milk procured from him otherwise than by a sampling officer, the defendant either—
(i)has within sixty hours after the sample was procured served such a notice as is mentioned in Article 41(2); or
(ii)not having served such a notice, proves that he had reasonable cause to believe that such a notice would have been of no effect by reason of the fact that the milk in question was a mixture of milk produced on more than one farm.
(3) Where the defendant is a servant of the person who purchased the article or substance under a warranty, he shall be entitled to rely on the provisions of this Article in the same way as his employer would have been entitled to do if he had been the defendant.
(4) The person by whom the warranty is alleged to have been given shall be entitled to appear at the hearing and to give evidence, and the court may, if it thinks fit, adjourn the hearing to enable him to do so.
(5) For the purposes of this Article and Article 59, a name or description entered in an invoice shall be deemed to be a written warranty that the article or substance to which the entry refers can be sold or otherwise dealt with under that name or description by any person without contravening any of the provisions of this Order or of regulations made under it.