(1) For the purposes of this section "transfer", other than the last-mentioned reference in paragraph (ii) of subsection (2), means a transfer which would but for this section be chargeable with stamp duty.
(2) A contract or agreement for the sale of any leasehold interest in any immovable property shall, if -
(a) the purchaser enters into possession of the property before having obtained a transfer, duly stamped, of such interest, and
(b) a transfer of such interest made in pursuance of the contract or agreement is not duly stamped within the period of 9 months from the first execution of the contract or agreement or such longer period as the Commissioners may specify in writing, being a period which they consider reasonable in all the circumstances of the case,
be charged with the same ad valorem stamp duty, to be paid by the purchaser, as if it were an actual transfer on sale of the leasehold interest contracted or agreed to be sold, and where the ad valorem stamp duty charged