Whenever the Commissioners determine to discontinue the use of any die, and provide a new die to be used in lieu thereof, and give public notice thereof in the London, Edinburgh, and Dublin Gazettes, then from and after any day to be stated in the notice (such day not being within one month after the same is so published) the new die shall be the only lawful die for denoting the duty chargeable in any case in which the discontinued die would have been used; and every instrument first executed by any person, or bearing date after the day so stated, and stamped with the discontinued die, shall be deemed to be not duly stamped:
Provided as follows:
(a) If any instrument stamped as last aforesaid, and first executed after the day so stated at any place out of the United Kingdom, is brought to the Commissioners within fourteen days after it has been received in the United Kingdom, then upon proof of the facts to the satisfaction of the Commissioners the stamp thereon shall be cancelled