(1) Notwithstanding anything contained in the Rating Act 1925, or any other Act, all lands and buildings situated in the City of Auckland for the time being vested in and actually used by the Institute for the purposes of any school, workroom, shop, gardens, recreation-grounds, residences, or residential quarters for blind persons and held otherwise than as an endowment shall be deemed not to be and never to have been rateable property for the purposes of the Rating Act 1925, and in respect thereof the Institute shall be exempt from liability for the payment of rates not being rates charged or levied for or in respect of water supplied by the Council in respect of such said lands and buildings as if the said lands and buildings had always been excluded from the definition of rateable property in the Rating Act 1925.