The registration of a rent for a dwelling-house takes effect—
If the rent for the time being registered is confirmed, the confirmation takes effect—
The date from which the registration or confirmation of a rent takes effect shall be entered in the register.
As from the date on which the registration of a rent takes effect any previous registration of a rent for the dwelling-house ceases to have effect.
Where a valid notice of increase under any provision of Part Ill 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.