(1)Unless the rent officer or, as the case may be, the rent assessment committee determine that it shall take effect as from a later date, the registration of any rent for a dwelling-house shall take effect—
(a)in a case where (by virtue of subsection (4) of section 67 of this Act) an application is made before the expiry of the period of three years referred to in subsection (3) of that section, as from the first day after the expiry of that period of 3 years;
(b)in a case where, on an application under section 8 of the [1975 c. 6.] Housing Rents and Subsidies Act 1975, a new rent has been substituted for the rent previously registered, as from the date as from which the registration of the rent for which the new registered rent was substituted took effect; and
(c)in any other case, as from the date of the application.
(2)The date from which the registration takes effect shall be entered in the register and as from that date any previous registration of a rent for the dwelling-house shall cease to have effect.
(3)Where a valid notice of increase under any provision of Part III of this Act has been served on a tenant and, in consequence of the registration of a rent, part but not the whole of the increase specified in the notice becomes irrecoverable from the tenant, the registration shall not invalidate the notice, but the notice shall, as from the date from which the registration takes effect, have effect as if it specified such part only of the increase as has not become irrecoverable.