(1) If, at any time and for any reason, it appears that no or insufficient duty has been paid to the Commissioners, they shall make an assessment of such amount of duty or additional duty as, to the best of their knowledge, information and belief, ought to be charged, levied and paid and the accountable person shall be liable for the payment of the duty so assessed.
(2) If, at any time and for any reason, it appears that an assessment is incorrect, the Commissioners shall make such other assessment as they consider appropriate and this other assessment shall be substituted for the first-mentioned assessment.
(3) An accountable person aggrieved by an assessment made on that person under this section may appeal the assessment to the Appeal Commissioners, in accordance with section 949I of the Taxes Consolidation Act 1997, within the period of 30 days after the date of the notice of assessment.
(4) In default of an appeal, in accordance with subsection (3), being made by an accountable pe
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