Paragraph 14
The portion of C's tax liability for the relevant accounting period that is to be treated as satisfied is an amount equal to the smaller of—
the tax reduction figure, and
the amount of C's tax liability for that period less any portion of that amount that is treated as satisfied in consequence of any qualifying gift made by C on a previous occasion.
The amount determined under sub-paragraph (1) may be nil.
The tax reduction figure is—
20% of the value set out in the agreed terms as the agreed value of the property forming the subject of the qualifying gift, or
such lower figure as may be specified in the agreed terms as the tax reduction figure.
The Treasury may by order substitute a different percentage for the percentage specified for the time being in sub-paragraph (3)(a).