(1)M1Any question arising under section 100(1)(a) or 101(1)(a) shall be determined as follows, for the purpose of computing for any tax purpose the profits or gains of both the trades or, as the case may be, the professions or vocations concerned—
(a)in a case where the same body of General Commissioners have jurisdiction with respect to both the trades, professions or vocations concerned, the question shall be determined by those Commissioners unless all parties concerned agree that it shall be determined by the Special Commissioners;
(b)in any other case, the question shall be determined by the Special Commissioners; and
(c)the General or Special Commissioners shall determine the question in like manner as an appeal.
(2)M2Where, by virtue of section 113 or 337(1), a trade, profession or vocation is treated as having been permanently discontinued for the purpose of computing tax, it shall also be so treated for the purposes of sections 100 and 101; but those sections shall not apply in a case where a trade, profession or vocation carried on by a single individual is discontinued by reason of his death.