put on the market by the proprietor or with the proprietor’s authorisation. (4) Where a person performs any of the acts referred to in paragraph (b) of subsection (1) in respect of¾ (a) a layout-design which is an unlawful reproduction of a registered layout-design; or (b) an integrated circuit incorporating an unlawfully reproduced layoutdesign referred to in paragraph (a); or (c) an article incorporating an integrated circuit referred to in paragraph (b); the act shall be lawful if, when the person acquired the layout-design, integrated circuit or article concerned, he did not know and had no reasonable grounds to know that the layout-design was an unlawful reproduction: Provided that, after he has received due notice that the layout-design concerned is an unlawful reproduction, he may perform any of those acts only in respect of stock which he had on hand when he received the notice or which he ordered before he received the notice and, if he does perform any of those acts in respect of that stock, he shall be liable to pay the proprietor of the registered layout-design a sum equivalent to a reasonable royalty such as would be payable under a freely negotiated licence in respect of such a layout-design. (5) Subject to this Act, the registration of a layout-design shall have the same effect against the State as it has against a subject. 16 Period of protection of registered layout-designs (1) The protection accorded to any registered layout-design by section fifteen shall commence¾ (a) on the date on which the design was first exploited commercially anywhere in the world by or with the authorisation of its proprietor; or (b) where the design has not been exploited commercially before its registration, on the effective date of its registration, as provided in section thirteen. (2) The protection accorded to any registered layout-design by section fifteen shall terminate at the end of the tenth calendar after the commencement of the protection in terms of subsection (1). PART V CORRECTION AND RECTIFICATION OF REGISTER AND CANCELLATION OF REGISTRATION 17 Power of Registrar to authorise corrections (1) The Registrar may authorise the correction of any clerical or similar error in the Register. (2) The Registrar may authorise a correction in terms of subsection (1) either on his own initiative or upon a request in writing made by any interested person and accompanied by the prescribed fee. (3) Where it is proposed to make a correction otherwise than upon a request in writing, the Registrar shall give notice of the proposal to the registered proprietor of the layout-design and to any other person who appears to him to be concerned, and shall give any such person an opportunity to be heard before the correction is made. 18 Rectification of Register (1) On the application of any aggrieved person, the Tribunal may order the Register to be rectified by the making or alteration of any entry in it or the deletion of any entry from it. (2) The Tribunal may determine any question which it may be necessary or expedient to decide in connection with the rectification of the Register. (3) Notice of any application to the Tribunal in terms of subsection (1) shall be given in the prescribed manner to the Registrar and to any other person appearing from the Register to be interested in the layout-design concerned, and the Registrar and any such person shall be entitled to appear and be heard in the application. (4) A notice of any order made by the Tribunal under this section shall be served on