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