(1) Subject to this Chapter, the amount of the profits or gains arising in any year shall for the purposes of Case V of Schedule D be computed as follows:
(a) the amount of any rent shall be taken to be the gross amount of that rent before any deduction for income tax;
(b) the amount of the profits or gains arising in any year shall be the aggregate of the surpluses computed in accordance with paragraph (c), reduced by the aggregate of the deficiencies as so computed;
(c) the amount of the surplus or deficiency in respect of each rent or in respect of the total receipts from easements shall be computed by making the deductions authorised by subsection (2) from the rent or total receipts from easements, as the case may be, to which the person chargeable becomes entitled in any year.
(2) The deductions authorised by this subsection shall be deductions by reference to any or all of the following matters -
(a) the amount of any rent payable by the person chargeable in respect of the premis
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