27.—(1) Subject to the following provisions of this regulation, in proceedings against any person for an offence under regulation 25 above it shall be a defence for that person to show that he took all reasonable steps and exercised all due diligence to avoid committing the offence.
(2) Where in any proceedings against any person for such an offence the defence provided by paragraph (1) involves an allegation that the commission of the offence was due—
(a)to the act or default of another; or
(b)to reliance on information given by another,
that person shall not, without the leave of the court, be entitled to rely on the defence unless, not less than seven clear days before the hearing of the proceedings (or, in Scotland, the trial diet), he has served a notice under paragraph (3) on the person bringing the proceedings.
(3) A notice under this paragraph shall give such information identifying or assisting in the identification of the person who committed the act or default or gave the information as is in the possession of the person serving the notice at the time he serves it.
(4) It is hereby declared that a person shall not be entitled to rely on the defence provided by paragraph (1) by reason of his reliance on information supplied by another, unless he shows that it was reasonable in all the circumstances for him to have relied on the information, having regard in particular—
(a)to the steps which he took, and those which might reasonably have been taken, for the purpose of verifying the information; and
(b)to whether he had any reason to disbelieve the information.