(1) For the purposes of section 23 the value of the turnover in the United Kingdom of the enterprise being taken over shall be determined by taking the total value of the turnover in the United Kingdom of the enterprises which cease to be distinct enterprises and deducting -
(a) the turnover in the United Kingdom of any enterprise which continues to be carried on under the same ownership and control; or
(b) if no enterprise continues to be carried on under the same ownership and control, the turnover in the United Kingdom which, of all the turnovers concerned, is the turnover of the highest value.
(2) For the purposes of this Part (other than section 121(4)(c)(ii)) the turnover in the United Kingdom of an enterprise shall be determined in accordance with such provisions as may be specified in an order made by the Secretary of State.
(3) An order under subsection (2) may, in particular, make provision as to -
(a) the amounts which are, or which are not, to be treated as comprising an en
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