20.—(1) In any proceedings against a person (A) for an offence under regulation 19 it is a defence for A to prove—
(a)that the commission of the offence was due to—
(i)the act or default of another, or
(ii)reliance on information given by another, and
(b)that A took all reasonable precautions and exercised all due diligence to avoid the commission of such an offence by A or any person under A’s control.
(2) A person is not entitled to rely on the defence provided by paragraph (1) without leave of the court unless—
(a)that person has served on the prosecutor a notice in writing giving such information as was in that person’s possession identifying or assisting in the identification of the other person; and
(b)the notice is served on the prosecutor not less than 7 days before the hearing of the proceedings or, in Scotland, 7 days before the intermediate diet or 14 days before the trial diet, whichever is earlier.