It shall be competent to the grantee under a general disposition within the sense and meaning of the nineteenth section of " The Titles to Land Consolidation (Scotland) Act, 1868," or to a person acquiring or deriving right from such grantee, to complete a title to an heritable security belonging to the granter of such general disposition, and in which such granter was infeft, by expeding and recording in the appropriate register of sasines a notarial instrument in, or as nearly as may be in, the form of Schedule N. hereto annexed, and on such notarial instrument being so expede and recorded the grantee or the person acquiring or deriving right from such grantee, as the case may be, in whose favour such instrument has been expede shall be vested with the full right of the creditor in such security, and shall be held to be entered with the superior in like manner and to the same effect as the original creditor himself. And it shall not be competent to challenge the validity of any notarial instrument expede and recorded before or after the commencement of this Act with reference to any heritable security in terms of the said nineteenth section of the said Act upon the ground that such notarial instrument is not in the form of Schedule (L.) annexed to the said Act, or that the said form is not adapted to heritable securities.