3Stamp duty shall not be chargeable on any instrument which is certified to the Commissioners of Inland Revenue by the Secretary of State as being a scheme under section 1 of this Act (or as having been made or executed in pursuance of such a scheme) and as effecting a transfer of property, rights or liabilities to a company all the issued shares in which are held by or on behalf of the Crown; but no such instrument shall be taken to be duly stamped unless—
(a)it is stamped with the duty to which it would but for this paragraph be liable; or
(b)it has, in accordance with section 12 of the [1891 c. 39.] Stamp Act 1891, been stamped with a particular stamp denoting that it is not chargeable with any duty or that it is duly stamped.