Regulation 17 Failure to comply with requirement to serve notice or other document
A defendant in proceedings for an offence under these regulations in respect of a contravention of article 1(1) of the Council regulation shall not be convicted of the offence if he proves that any notice or other document required to be served on him by regulation 7, 8(1), (2) or 3, or 9(4) or (5) of these regulations was not served on him in compliance with the appropriate requirement, unless the court is satisfied either—
that the enforcement authority or, as the case may be, the authorised officer could not with reasonable diligence have ascertained the name and address of the defendant in time for the notice or other document to be served on the defendant in compliance with the appropriate requirement, or
that the defendant by his own conduct or by the conduct of his employee contributed to the failure of the enforcement authority or, as the case may be, the authorised officer to comply with the appropriate requirement.