(i)that the premises consist of not more than two floors and the same are required by the landlord for the purpose of immediate demolition with a view to rebuild the same. Provided that where the building of which such premises or premises possession in respect of which has been recovered under clause (e). clause (f), clause (g) or clause (h) forms apart has been rebuilt to an extent of less than seventy-five per cent., a tenant so dispossessed shall have a right to reentry at the new terms of tenancy in a premises in the rebuilt building equivalent in area to the original premises for which he was a tenant;