(1) In this section "residential consideration" means - (a) in the case of a sale to which section 45(2)(a) refers, or a lease to which section 52(5)(a) refers, the amount or value of the consideration for the sale or lease which is deemed to be attributable to residential property, and (b) in the case of a sale to which section 45(2)(b) refers, or a lease to which section 52(5)(b) refers, the amount or value of the aggregate consideration (within the meaning of section 45(2) or 52(5), respectively) which is deemed to be attributable to residential property.
(2) Where -
(a) in relation to any sale, section 45 (2) refers, an estimate (in this section referred to as the "vendor's estimate" or as the "purchaser's estimate", as the case may be) of the residential consideration shall be made by the vendor and by the purchaser, and
(b) in relation to any lease, section 52 (5) refers, an estimate (in this section referred to as the "lessor's estimate" or as the "lessee's estimate",