“savings certificates” means savings certificates issued under section 12 of the [1968 c. 13.] National Loans Act 1968, or section 7 of the [1958 (7 Eliz. 2) c.6.] National Debt Act 1958, or section 59 of the [1920 c. 18.] Finance Act 1920, and any war savings certificates as defined in section 9(3) of the [1972 c. 65.] National Debt Act 1972, together with any savings certificates issued under any enactment forming part of the law of Northern Ireland and corresponding to the said enactments, and

“non-marketable securities” means securities which are not transferable, or which are transferable only with the consent of some Minister of the Crown, or the consent of a department of the Government of Northern Ireland, or only with the consent of the National Debt Commissioners.