3 Edw. 7. c. 36.
Provided that any number which has been assigned to a motor car under section two of the Motor Car Act, 1903, and which is the registered number of that car on the first day of January, nineteen hundred and twenty-one, shall be treated as having been assigned to the car under the provisions of this section and no new number shall be assigned to such a car.
Provided that a person charged under this section with obscuring a mark or rendering or allowing it to become not easily distinguishable, shall not be liable to be convicted on the charge if he proves that he has taken all steps reasonably practicable to prevent the mark being obscured or rendered not easily distinguishable.
A person shall not be liable to a penalty under this section if he proves that he has had no reasonable opportunity of registering the vehicle in accordance with this section, and that the vehicle is being driven on a public road for the purpose of being so registered.