Where a drainage board make a determination under section 43 above, they shall serve notice of the determination, together with a statement in writing of the rights of appeal conferred by section 45 below, on the occupier of the chargeable property to which the determination relates.
Subject to regulations under section 41A above and to section 46 below (and notwithstanding anything in section 41 above), where a determination of annual value under section 43 above is made in pursuance of section 43(1) above, the annual value of the property in question shall, for the purposes of any drainage rate made after the effective date, be that specified in the determination.
Subject to regulations under section 41A above and to section 46 below (and notwithstanding anything in section 41 above), where a determination of annual value under section 43 above is made in pursuance of section 43(2) above, the annual value of the property in question shall for the purposes of—
be that specified in the determination.
Where—
that amount shall be recalculated accordingly and any sum overpaid shall be repaid or allowed, and any sum underpaid may be recovered as if it were arrears of drainage rates.
In this section "the effective date", in relation to a determination under section 43 above, means the date on which notice of the determination is served in pursuance of subsection (1) above on the occupier of the chargeable property to which the determination relates.