50.—F70[(1)] If, in determining the net annual value of property or any part of it in accordance with section 48, a method of valuation relying on the notional cost of constructing or providing the property or part is used, then, notwithstanding subsection (3) of that section, the net annual value of the property or part, for the purposes of that section, F71[shall, subject to subsection (2), be an amount] equal to 5 per cent of the aggregate of the replacement cost, depreciated where appropriate, of the property or part and the site value of the property or, as the case may be, part.

F70[(2) An adjustment shall be made so that the amount arrived at by such means to be the property’s net annual value is (insofar as is reasonably practicable and in accordance with section 19(5) or 49, as appropriate) determined by reference to the values of other properties comparable to that property as appearing on the valuation list.]