Prototypes
18. Regulation 16 shall not apply in relation to a vehicle of a new or improved construction, or a vehicle fitted with new or improved equipment, which–
(a)has been so constructed, or fitted with such equipment, for the purposes of tests or trials or for use as a prototype, and
(b)is not intended for general use on roads, and
(c)remains in the ownership and use of the manufacturer of the vehicle or (as the case may be) the manufacturer of the equipment.