This section applies to every appeal brought under section 23B.
In determining an appeal the CMA must have regard, to the same extent as is required of the Authority, to the matters to which the Authority must have regard—
in the carrying out of its principal objective under section 4AA;
in the performance of its duties under that section; and
in the performance of its duties under sections 4AB and 4A.
In determining the appeal the CMA —
may have regard to any matter to which the Authority was not able to have regard in relation to the decision which is the subject of the appeal; but
must not, in the exercise of that power, have regard to any matter to which the Authority would not have been entitled to have regard in reaching its decision had it had the opportunity of doing so.
The CMA may allow the appeal only to the extent that it is satisfied that the decision appealed against was wrong on one or more of the following grounds—
that the Authority failed properly to have regard to any matter mentioned in subsection (2);
that the Authority failed to give the appropriate weight to any matter mentioned in subsection (2);
that the decision was based, wholly or partly, on an error of fact;
that the modifications fail to achieve, in whole or in part, the effect stated by the Authority by virtue of section 23(7)(b);
that the decision was wrong in law.
To the extent that the CMA does not allow the appeal, it must confirm the decision appealed against.