The appointed day fixed under section sixty-one of the Act shall, in respect of the Board, for all purposes be and be deemed to have been the first day of April, nineteen hundred and forty-six, and every act, resolution, order, licence, notice, by-law, and document done, passed, issued, given, made, or executed by the Board at any time for the purposes of the Act which would have been valid if the resolution had been duly confirmed as a special order under section forty-two of the Act is hereby declared to have been lawfully done, passed, issued, given, made, or executed, as the case may require, and shall have effect according to the tenor thereof.