(1) Where the Appeal Commissioners -
(a) are satisfied that an appeal is not a valid appeal,
(b) become aware, having previously formed the view that an appeal was a valid appeal, that it is not a valid appeal, or
(c) are satisfied that an appeal is without substance or foundation, they shall refuse to accept the appeal.
(2) Where the Appeal Commissioners refuse to accept an appeal, they shall notify the parties in writing accordingly stating the reason for the refusal.
(3) Where, in respect of a refusal on their part to accept an appeal, the Appeal Commissioners declare that their decision in that regard is final, then that decision shall be final and conclusive.
(4) For the avoidance of doubt -
(a) references in the preceding subsections to the Appeal Commissioners' refusing to accept an appeal include references to a member or members of staff of the Commission, pursuant to an authority granted under section 5(2) of the Finance (Tax Appeals) Act 2015, refusing to accept an appeal, a
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