16(1)An agreement by which the person by whom a trade, profession or vocation is carried on agrees to sell or transfer trading stock or work in progress is a self-cancelling transaction for the purposes of paragraph 15 above if by the same or any collateral agreement that person—
(a)agrees to buy back or re-acquire the trading stock or work in progress; or
(b)acquires or grants an option, which is subsequently exercised, for him to buy back or re-acquire the trading stock or work in progress.
(2)In sub-paragraph (1) above—
“trading stock” has the same meaning as in section 100 of the Taxes Act 1988;
“work in progress”, in relation to a profession or vocation, means—
(a)any services performed in the ordinary course of the profession or vocation, the performance of which is wholly or partly completed at the time of the sale or transfer and for which it would be reasonable to expect that a charge would have been made on their completion if the sale or transfer had not been effected; and
(b)any article produced, and any such material as is used, in the performance of any such services,
and references in that sub-paragraph to the sale or transfer of work in progress shall include references to the sale or transfer of any benefits and rights which accrue, or might reasonably be expected to accrue, from the carrying out of the work.