(1) Subject to subsection (2) -

(a) where for any year of assessment or accounting period, as the case may be, relief from any tax referred to in section 1080(2) is given to any person by a discharge of any of that tax, such adjustment shall be made of the amount of interest payable under that section in relation to that tax, and such repayment shall be made of any amounts of interest previously paid under that section in relation to that tax, as are necessary to secure that the total sum, if any, paid or payable under that section in relation to that tax is the same as it would have been if the tax discharged had never been due and payable, and

(b) where relief from tax paid for any year of assessment or accounting period, as the case may be, is given to any person by repayment, that person shall be entitled to require that the amount repaid shall be treated for the purposes of this subsection to the extent possible as if it were a discharge of the tax charged on that person (whether alone or together with other persons) by any assessment for the same year or period; but the relief shall not be applied to any assessment made after the relief was given and shall not be applied to more than one assessment so as to reduce without extinguishing the amount of tax charged thereby.

(2) No relief, whether by discharge or repayment, shall be treated as affecting any tax charged by an assessment to -

(a) income tax or any income tax due and payable unless it is a relief from income tax,