7So much of the provisions of Part IV of this Act relating, to income tax on sums paid as or on account of post-war refunds as provides that the right to elect that sums so paid shall be chargeable as profits and gains of a trade for the year 1947-48 in lieu of being chargeable to tax for the year 1946-47 shall be restricted to cases where the person to whom the sum is paid is carrying on the trade during the whole or some part of the year 1947-48 shall not apply where, during the whole or part of the year 1947-48, the trade is being carried on by a subsidiary member of a group of companies of which the person to whom the sum was paid is then the principal, company.