Section 659 of the Principal Act is hereby amended in subsection (3) by the substitution of the following paragraph for paragraph (a):
"(a) as respects the first year of the writing-down period referred to in subsection (2), where the capital expenditure was incurred -
(i) before the 6th day of April, 1998, an amount equal to 50 per cent of that expenditure or £10,000, whichever is the lesser, or
(ii) on or after the 6th day of April, 1998, an amount equal to 50 per cent of that expenditure or £15,000, whichever is the lesser,".