49. (1) The Registrar shall not, in exercise of any power conferred on him under clause (a) of sub-section (2) of section 84, make any amendment of the register which would have the effect of adding any goods or classes of goods to those in respect of which a trade mark is registered (whether in one or more classes) immediately before the amendment is to be made or of antedating the registration of a trade mark in respect of any goods: Provided that this sub-section shall not apply when the Registrar is satisfied that compliance therewith would involve undue complexity and that the addition or antedating, as the case may be, would not affect any substantial quantity of goods and would not substantially prejudice the rights of any person. (2) A proposal so to amend the register shall be notified to the registered proprietor of the trade mark affected and advertised in the prescribed manner, and may be opposed before the Registrar by any person aggrieved on the ground that the proposed amendment contravenes the provisions of sub-section (1).