29. (1) With respect to the provisions made by this section and section 30 —

(a) those provisions supplement section 27(2), and

(b) so far as those provisions provide for the taking of steps after the commencement date, those provisions shall be read as providing for those steps to be taken under Part 40A (or under that Part in conjunction with the additional provision made by those provisions),

and, following the taking of such steps, the provisions otherwise of Part 40A shall apply accordingly.

(2) If—

(a) any of the steps in the stating and signing of a case for the opinion of the High Court on the determination of the Appeal Commissioners remain to be taken before the commencement date, and

(b) the one or more Appeal Commissioners who heard the appeal have vacated, in whatever circumstances, office,

the vacation of office by those Appeal Commissioners shall not prevent the application of section 27(2) to the taking of such steps, which steps may be taken after the commencement date by one or more other Appeal Commissioners.

(3) Subsection (4) applies if the circumstances referred to in subsection (2)(a) apply in the particular case, irrespective of whether the circumstances referred to in subsection (2)(b) also apply in the particular case (and if the circumstances referred to in both of those paragraphs so apply subsection (4) applies notwithstanding that subsection (2) provides for certain steps to be taken by Appeal Commissioners other than the one or more Appeal Commissioners who heard the appeal referred to in that subsection).

(4) Where this subsection applies, the Appeal Commissioners shall serve a notice on each of the parties to the appeal, the subject of the proposed case stated, requesting the party to state to the Appeal Commissioners, within a period specified in the notice, whether the party wishes—

(a) the Appeal Commissioners to rehear the appeal, or

(b) the completion and signing of the case stated to be proceeded with.

(5) Where both of the parties state to the Appeal Commissioners, within the period specified in the notice concerned under subsection (4) —

(a) that they wish the appeal to be reheard by the Appeal Commissioners, the appeal shall be reheard by the Commissioners, or

(b) that they wish the completion and signing of the case stated to be proceeded with—

(i) subject to subparagraph (ii), the Commissioners shall complete the case stated and sign it, or

(ii) if section 30 applies, the Commissioners shall comply with that section and complete the case stated and sign it in accordance with that section.

(6) Subject to subsection (7), if the service of a notice under subsection (4) does not result in a statement that falls within subsection (5)(a) or (b), the Appeal Commissioners shall complete the case stated and sign it.

(7) If—

(a) the service of a notice under subsection (4) does not result in a statement that falls within subsection (5)(a) or (b), and

(b) section 30 applies,

the Appeal Commissioners shall comply with that section and complete the case stated and sign it in accordance with that section.

(8) Subsection (9) applies to a case stated sent to the High Court in circumstances in which, by virtue of this section (or this section and section 30), a case stated may be completed and signed by Appeal Commissioners other than the one or more Appeal Commissioners who heard the appeal, the subject of the case stated, and the reference in subsection (9) to the relevant circumstances is a reference to both—

(a) the fact of the second-mentioned Commissioners in this subsection having vacated, in whatever circumstances, office, and

(b) the fact of the case stated having been completed and signed by the first-mentioned Commissioners in this subsection.

(9) If, on or after the sending to it of a case stated to which this subsection applies, the High Court is of the opinion that having regard to—

(a) the particular issues arising in the case stated, or

(b) the likelihood of there being exercised by it the powers under section 949AR(1)(b) or (2) of the Act of 1997 in relation to the case stated,

the proceeding by it to deal, or further deal, with the case stated would not, by reason of the relevant circumstances, be consistent with the due administration of justice, it shall decline to deal, or further deal, with the case stated and may make an order directing that the appeal, the subject of the case stated, be reheard by the Appeal Commissioners or such other order as it deems just.