7.—(1) The motor vehicle comprised in the articulated vehicle must be being used for the conveyance of a loading unit as part of a combined transport operation, the loading unit being on a journey—
(a)to a railhead from which the loading unit is, as part of the operation, to be transported in a relevant manner by railway pursuant to a relevant contract made before the journey began; or
(b)from a railhead to which the loading unit has, as part of the operation, been transported in a relevant manner by railway; or
(c)to a harbour from which the relevant receptacle is, as part of the operation, to be transported by sea pursuant to a relevant contract made before the journey began; or
(d)from a harbour to which the relevant receptacle has, as part of the operation,been transported by sea.
(2) If the loading unit is a bi-modal vehicle, the semi-trailer comprised in the articulated vehicle must be the bi-modal vehicle in its semi-trailer mode.
(3) If the loading unit is a relevant receptacle, the relevant receptacle must be being carried on the semi-trailer comprised in the articulated vehicle.
(4) There must be carried in the cab of the motor vehicle a document or documents—
(a)if the vehicle is on a journey to a railhead, specifying the railhead, the date the contract was made and the parties thereto;
(b)if the vehicle is on a journey from a railhead, specifying the railhead and the date and time at which the loading unit was collected from that railhead;
(c)if the vehicle is on a journey to a harbour, specifying the harbour, the date the relevant contract was made and the parties thereto; and
(d)if the vehicle is on a journey from a harbour, specifying the harbour and the date and time at which the receptacles were collected from that harbour.