(a) This section applies to immovable goods -
(i) which have been developed by or on behalf of the person supplying them, or
(ii) in respect of which the person supplying them was, or would, but for the operation of section 3(5)(b) (iii), have been at any time entitled to claim a deduction under section 12 for any tax borne or paid in relation to a supply or development of them.
(b) In this section "interest", in relation to immovable goods, means an estate or interest therein which, when it was created was for a period of at least ten years or, if it was for a period of less than ten years, its terms contained an option for the person in whose favour the interest was created to extend it to a period of at least ten years, but does not include a mortgage, and a reference to the disposal of an interest includes a reference to the creation of an interest, and an interval of the type referred to in subsection (2A) shall be deemed to be an interest for the purposes of this section