23.—(1) If, in proceedings before a magistrates’ court for an offence under these Regulations, a defendant intends to produce a certificate issued under paragraph 19, or to require that the person by whom a certificate was issued be called as a witness, the defendant must give notice of that intention and (where a certificate is to be produced) a copy of the certificate to the other party at least three clear days before the day on which the summons is returnable.
(2) If sub-paragraph (1) is not complied with the court may adjourn the hearing on such terms as it thinks fit.
(3) In Scotland, if in proceedings in the sheriff court for an offence under these Regulations the accused intends to produce a certificate under paragraph 19, or to require that the person by whom a certificate was issued be called as a witness, the accused must give notice of that intention and (where a certificate is to be produced) a copy of the certificate to the procurator fiscal at least three clear days before the day on which the case proceeds to trial.
(4) If sub-paragraph (3) is not complied with the sheriff may adjourn the diet on such terms as the sheriff thinks fit.