Sections 53 to 57, 104, 108, 109, 110, 113, 114, 131 and 145 shall apply with any necessary modifications in relation to assets forming part of a premiums trust fund as they apply in relation to other assets, and for the purposes of the application of those sections in accordance with this section, it shall be assumed—
(a)that assets forming part of a fund are disposed of and immediately reacquired on the last day of each accounting period; and
(b)that the indexation allowance computed for that accounting period is allocated to the corresponding underwriting year in the same proportion as the gains or losses referred to in section 207(2).