1) Any person, other than the Board or any of its officers aggrieved by any decision or order passed under sections 76 by an officer authority may, within thirty days of the date of receipt of such decision or order, prefer appeal to the Commissioner (Appeals)

2) Provided that an appeal preferred after the expiry of thirty days may be admitted by the Commissioner (Appeals) if he is satisfied that the appellant has sufficient cause for not preferring the appeal within the specified period: