Paragraph 4
A goods vehicle falls within this paragraph if it forms part of an articulated combination which is such that—
(a)
in a case where the trailer comprised in the combination has a relevant plated weight, the aggregate of—
(i)
the unladen weight of the motor vehicle comprised in the combination, and
(ii)
the relevant plated weight of that trailer,
does not exceed 3.5 tonnes, or
(b)
in any other case, the aggregate of the unladen weights of the motor vehicle and the trailer comprised in the combination does not exceed 1525 kilograms.