6(1)An assessment shall not be made under this Schedule at any time on or after 1st December 2003.U.K.
(2)Where an assessment is made under this Schedule, notice of that assessment shall be served on the company assessed.
(3)The notice of any assessment under this Schedule must state—
(a)the date on which it is issued; and
(b)the time within which any appeal against the assessment may be made.
(4)After the notice of any assessment under this Schedule has been served on the company assessed—
(a)the assessment shall not be withdrawn;
(b)the assessment shall not be amended, except in accordance with provision made or applied by this Schedule; and
(c)the company shall not, except in accordance with any provision so made or applied, be entitled to the repayment of any amount on the grounds that the amounts of windfall tax assessed on that company are excessive.
(5)Where notice of any assessment under this Schedule has been served on the company assessed, the amount of the assessment—
(a)shall be deemed (subject to the provisions of this Schedule) to be an amount of windfall tax with which that company is charged; and
(b)subject to the provisions of this Part about the payment of windfall tax in instalments, may be recovered accordingly.
(6)Liability to pay an instalment of windfall tax does not depend on the making of an assessment; and nothing in the provisions of this Schedule about the making of assessments shall affect the times which are taken for the purposes of this Part to be the times by which companies are required under paragraph 3 above to pay instalments of windfall tax.