Where a district judge had decided a preliminary issue as to jurisdiction his ruling could properly be challenged by way of case stated or judicial review. An offence under s1(1)(a) of the Trade Descriptions Act 1968 was a separate offence from that created by s1(1)(b) and was committed at the time when an odometer reading was altered. The local authority rather than one of its officers was the prosecutor within the meaning of s19 of the 1968 Act and it discovered an offence under that section when one of its officers first became aware of the offence.