4.—(1) A person employed by virtue of paragraph 1 must be additional to the person or persons employed to drive the vehicle.
(2) Where three or more vehicles are travelling together in convoy, only the rearmost and foremost vehicles in the convoy must be accompanied by an attendant.
(3) Any person or persons employed in driving a motor vehicle for the purpose of assisting the propulsion of another vehicle is not to be treated as an attendant in relation to that other vehicle.