Where the purchase of any furniture has been required as a condition of the grant, renewal, continuance or assignation—
(a)of a protected tenancy, or
(b)of rights under a Part VII contract which relates to a dwelling-house falling within section 85(1) above,
then, if the price exceeds the reasonable price of the furniture, the excess shall be treated, for the purposes of this Part of this Act, as if it were a premium required to be paid as a condition of the grant, renewal, continuance or assignation of the protected tenancy or, as the case may be, the rights under the Part VII contract.