(1) In this section -
''basis period'' has, subject to any necessary modification, the meaning assigned to it in section 306;
"qualifying expenditure" means the amount of expenditure incurred in relation to a vehicle to which this Part applies, being expenditure which but for this section -
(a) would be allowable as a deduction -
(i) in the computation of the profits or gains chargeable to tax under Schedule D of the trade, profession or business in the course of which the vehicle is used, or
(ii) in the computation of the profits or gains chargeable to tax under Schedule E from an office or employment in the performance of the duties of which the vehicle is used,
or
(b) would be taken into account for the purposes of a claim in respect of expenses of management under section 83 or under that section as applied by section 707;
"relevant amount" means -
(a) in relation to qualifying expenditure incurred before the 23rd day of January, 1997, £14,000,
(b) in relation to qualifying e