s 77C Joint and several liability under section 77B or 77BA : assessments
(1) The Commissioners may assess the amount of VAT due from the operator of an online marketplace by virtue of section 77B or 77BA to the best of their judgment and notify it to the operator. (2) Subject to subsections (3) to (6), an assessment may be made for such period or periods as the Commissioners consider appropriate. (3) An assessment for any month may not be made after the end of— (a) 2 years after the end of that month, or (b) (if later) one year after evidence of facts, sufficient in the opinion of the Commissioners to justify the making of an assessment for that month, comes to their knowledge. (4) Subsection (5) applies if, after the Commissioners have made an assessment for a period, evidence of facts sufficient in the opinion of the Commissioners to justify the making of a further assessment for that period comes to their knowledge. (5) The Commissioners may, no later than one year after that evidence comes to their knowledge, make a further assessment for that period (subject to subsection (6)). (6) An assessment or further assessment for a month may not be made more than 4 years after the end of the month. (7) An amount which has been assessed and notified to a person under this section is deemed to be an amount of VAT due from the person and may be recovered accordingly (unless, or except to the extent that, the assessment is subsequently withdrawn or reduced). (8) Subsection (7) is subject to the provisions of this Act as to appeals. (9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .