13.—(1) A specified load is one of the following kinds of load—
(a)a test load;
(b)in the case of a vehicle which is being delivered or collected and is being used for a purpose falling within paragraph 12(f) to (k), a load which consists of another vehicle used or to be used for travel from or to the place of delivery or collection;
(c)a load which is built in as part of the vehicle or permanently attached to it;
(d)in the case of a vehicle which is being used for a purpose falling within paragraph 12(h), (i) or (j), a load which consists of a trailer or of parts, accessories or equipment designed to be fitted to the vehicle and of tools for fitting them.
(2) In paragraph (1) a “test load” means a load which—
(a)is carried by a vehicle being used for a purpose falling within paragraph 12(b), (d), (e) or (g);
(b)is carried solely for the purpose of testing or demonstrating the vehicle or any of its accessories or equipment; and
(c)is returned to the place of loading without its having been removed from the vehicle except—
(i)for the purpose of testing or demonstrating the vehicle or any of its accessories or equipment,
(ii)in the case of accident, or
(iii)where the load consists of water, fertiliser or refuse.