Subject to the provisions of this section it shall not be lawful to sell, or to supply, or to offer to sell or supply, a motor vehicle or trailer for delivery in such a condition that the use thereof on a road in that condition would be unlawful by virtue of any provision made by regulations under section 40 of this Act as respects brakes, steering gear or tyres or as respects the construction, weight or equipment of vehicles, or in such a condition, as respects lighting equipment or reflectors or the maintenance thereof, that it is not capable of being used on a road during the hours of darkness without contravention of the requirements imposed by law as to obligatory lamps or reflectors.
Subject to the provisions of this section it shall not be lawful to alter a motor vehicle or trailer so as to render its condition such that the use thereof on a road in that condition would be unlawful by virtue of any provision made as respects the construction, weight or equipment of vehicles by regulations under the said section 40.
If a motor vehicle or trailer is sold, supplied, offered or altered in contravention of the provisions of this section, any person who so sells, supplies, offers or alters it, or causes or permits it to be so sold, supplied, offered or altered, shall be guilty of an offence.
A person shall not be convicted of an offence under this section in respect of the sale, supply, offer or alteration of a motor vehicle or trailer if he proves—
(a) that it was sold, supplied, offered or altered, as the case may be, for export from Great Britain, or
(b) that he had reasonable cause to believe that the vehicle or trailer would not be used on a road in Great Britain, or would not be so used until it had been put into a condition in which it might lawfully be so used, or
(c) in the case of a vehicle or trailer the sale, supply or offer of which is alleged to be unlawful by reason of its condition as respects lighting equipment or reflectors or the maintenance thereof, that he had reasonable cause to believe that the vehicle or trailer would not be used on a road in Great Britain during the hours of darkness until it had been put into a condition in which it might be so used during those hours without contravention of the requirements imposed by law as to obligatory lamps or reflectors.
Nothing in the foregoing provisions of this section shall affect the validity of a contract or any rights arising under a contract.
In this section " obligatory lamps or reflectors " means, in relation to a motor vehicle or trailer, the lamps or reflectors required by law to be carried thereon while it is on a road during the hours of darkness and when it is neither drawing nor being drawn by another vehicle, except that the said expression does not, in the case of a motor vehicle, include any lamps or reflectors required to be carried by virtue of section 79 of this Act, or, in the case of a trailer, include any lamps or reflectors so required to be carried or any lamps showing a white light to the front