17.—(1) The income from a trade, business or gainful occupation other than an occupation at a wage or salary shall be deemed to be whichever of the following the Tribunal considers more appropriate and practicable—
(a)the profits which have accrued or will accrue to the individual in respect of the period of calculation; or
(b)the drawings of the individual.
(2) In calculating the profits under paragraph (1)(a)—
(a)the Tribunal may have regard to the profits of the last accounting period of such trade, business or gainful occupation for which accounts have been prepared; and
(b)there shall be deducted all sums necessarily expended to earn those profits, but no deduction shall be made in respect of the living expenses of the individual or any member of his family or household, except in so far as that person is wholly or mainly employed in that trade or business and such living expenses form part of his remuneration.