2For the purposes of this Act, wine or made-wine shall be regarded as having been rendered sparkling if—
(a)as a result of aeration, fermentation or any other process, it either falls within paragraph 1(1) above or takes on such characteristics as are referred to in paragraph 1(2) above; or
(b)being sparkling wine or made-wine which, by virtue only of paragraph 1(3) above, was not chargeable to duty as sparkling wine or made-wine, it is transferred into a closed container which has a mushroom-shaped stopper (whether solid or hollow) held in place by a tie or fastening.