(b)where in a suit for infringement the defendant satisfies the court—(i)that at the time he commenced to use the trade mark complained of in the suit, he was unaware and had no reasonable ground for believing that the trade mark of the plaintiff was on the register or that the plaintiff was a registered user using by way of permitted use; and(ii)that when he became aware of the existence and nature of the plaintiff’s right in the trade mark, he forthwith ceased to use the trade mark in relation to goods or services in respect of which it was registered; or