Section 360 of the Principal Act is hereby amended -
(a) by the substitution of the following for the definition of "qualifying period":
"'qualifying period' means the period commencing on the 1st day of August, 1996, and ending on -
(a) the 31st day of July, 1999, or
(b) the 31st day of December, 1999, where, in relation to the construction of, conversion into, refurbishment of, or, as the case may be, construction or refurbishment of a house which is a qualifying premises within the meaning of section 361, 362, 363, or 364, the relevant local authority gives a certificate in writing, on or before the 31st day of October, 1999, to the person constructing, converting or refurbishing, as the case may be, the house stating that it is satisfied that not less than 50 per cent of the total cost of the house and the site thereof had been incurred on or before the 31st day of July, 1999;",
and
(b) by the insertion of the following definition after the definition of "qualifying period":
"'the
…