(1) In this section -
'qualifying lease', in relation to a house, means, subject to section 380E(2), a lease of the house the consideration for the grant of which consists -
(a) solely of periodic payments all of which are or are to be treated as rent for the purposes of Chapter 8 of Part 4, or
(b) of payments of the kind mentioned in paragraph (a), together with a payment by means of a premium which does not exceed 10 per cent of the relevant cost of the house;
'qualifying premises' means, subject to subsections (3), (4)(a), (5) and (6) of section 380E, a house -
(a) the site of which is wholly within a qualifying area,
(b) which is used solely as a dwelling,
(c) the total floor area of which complies with the requirements of the relevant guidelines,
(d) in respect of which, if it is not a new house (for the purposes of section 4 of the Housing (Miscellaneous Provisions) Act, 1979) provided for sale, there is in force a certificate of reasonable cost, the amount specified in