(1)For the purposes of section 30 the relevant period is the period—
(a)ending with the date on which the offence was committed, and
(b)beginning as provided by subsections (2) to (4).
(2)Subject to subsection (4), if the person convicted has before the date of the offence notified the Secretary of State of his acquisition of the vehicle in accordance with regulations made by the Secretary of State, the relevant period begins with—
(a)the date on which the notification was received by the Secretary of State, or
(b)the expiry of the vehicle licence last in force for the vehicle,
whichever is the later.
(3)Subject to subsection (4), in any other case the relevant period begins with—
(a)the expiry of the vehicle licence last in force for the vehicle before the date on which the offence was committed, or
(b)if there has not at any time before that date been a vehicle licence in force for the vehicle, the date on which the vehicle was first kept by the person convicted.
(4)Where—
(a)the person convicted has been ordered to pay an amount under section 30 on the occasion of a previous conviction for an offence in respect of the same vehicle, and
(b)that offence was committed after the date specified in subsection (2) or (3) as the date with which the relevant period begins,
the relevant period instead begins with the month immediately following that in which the earlier offence was committed.
(5)Where the person convicted proves—
(a)that throughout any month or part of a month in the relevant period the vehicle was not kept by him, or
(b)that he has paid the duty due (or an amount equal to the duty due) in respect of the vehicle for any such month or part of a month,
any amount which the person is ordered to pay under section 30 is to be calculated as if that month or part of a month were not in the relevant period.
(6)Where a person has previously been ordered under section 36 to pay an amount for a month or part of a month in the case of a vehicle, any amount which he is ordered to pay under section 30 in the case of the vehicle is to be calculated as if no part of that month were in the relevant period.
(7)In this section references to the expiry of a vehicle licence include a reference to—
(a)its surrender, and
(b)its being treated as no longer in force for the purposes of subsection (2) of section 29 by subsection (4) of that section.
(8)In the case of a conviction for a continuing offence, the offence is to be taken for the purposes of this section to have been committed on the date or latest date to which the conviction relates.