Where any local authority which is a planning authority under this Act has been dissolved or superseded and in its place any person has been appointed to carry on the administration of such local authority under any law for the time being in force relating to such local authority, then, notwithstanding anything contained in this Act or in any other law for the time being in force relating to such local authority, the person so appointed in the place of such local authority shall be deemed to be a planning authority for the purposes of this Act, until such local authority has been duly reconstituted under such law relating to such local authority.