4SA certificate by the Secretary of State that the whole of the loan has been repaid or that such terminable annuity has been redeemed shall, without any other instrument, operate as a discharge of the loan or extinction of the terminable annuity, as the case may be, and the recording of such certificate in the Register of Sasines or the registration of the certificate in the Land Register of Scotland shall be equivalent to the recording or the registration of a discharge of the said heritable security.