"A person who drives a motor vehicle on a road at a speed exceeding a limit imposed by or under any enactment to which this section applies shall be guilty of an offence."
"A magistrates' court may vary or rescind a sentence or other order imposed or made by it when dealing with an offender, if it appears to the court to be in the interests of justice to do so, and it is hereby declared that this power extends to replacing sentence or order which for any reason appears to be invalid by another which the court has power to impose or make."