(1) The use of an unregistered vehicle to which a trader's plate is attached is an authorised use if—
(a) the vehicle (or, for a trailer, the vehicle towing it) is carrying the person to whom the plate was issued (the trader ), the trader's authorised employee or the trader's agent authorised in writing; and
(b) the vehicle is being driven—
(i) for a purpose related to its manufacture or repair (including painting or a similar process) or related to, or incidental to, dealing in the vehicle; or
(ii) for the purpose of obtaining registration of the vehicle, by the most direct or convenient route to the nearest convenient designated place or authorised examiner; or
(iii) for delivery at the address of a person who has acquired it from the trader.
(2) However, subregulation (1) authorises the use of the unregistered registrable vehicle to carry a load only if—
(a) the load is carried only to demonstrate to a genuine prospective purchaser the capacity of the vehicle for carrying a type or weight of load; or
(b) the vehicle is being driven by the most direct or convenient route to the premises of the trader from the place where the trader has built or purchased the vehicle and the load consists only of a registrable vehicle built or purchased by the trader for sale by the trader; or
(c) the vehicle is a trailer specially built to carry a boat and the load consists only of a boat; or
(d) the vehicle is not heavier than 2t unladen and is being driven—
(i) by the shortest practicable route to the premises of the trader from the place where the trader has built or purchased the vehicle and the load consists only of goods intended for the trader's personal use or for use in his or her business; or
(ii) only for carrying spare parts, for use in relation to the repair of registrable vehicles by the trader, to the trader's premises from a railway station or airport to which they have been consigned to the trader.