(1) Where -

(a) a vehicle exceeding 17,000 kilograms in weight laden (within the meaning of the relevant regulations), or a combination of vehicles of which such a vehicle forms a part, is used on a public road,

(b) the owner is convicted of an offence under section 12 of the Principal Act in respect of such use, and

(c) the excess weight during such use was not less than 1,000 kilograms,

the court which so convicted shall, in addition to any penalty which may be imposed under section 12 of the Principal Act (as amended by the Road Traffic (Amendment) Act, 1984), impose on the owner so convicted a penalty fixed in accordance with the Table to this section.

(2) A penalty imposed under this section shall be paid to the road authority responsible for the maintenance of the road on which the offence was committed.

(3) Where a sum becomes recoverable under section 17 of the Principal Act and a penalty has been imposed under this section in respect of the same facts, the sum shall be reduced by the amount of the penalty.