32(1) The Commissioners shall
not be liable, on any claim for a repayment of aggregates levy, to
repay any amount paid to them more than 4 years before the making
of the claim.
32(2) In the case of any claim
for a repayment of an amount of aggregates levy other than a claim
to a repayment to which a person is entitled by virtue of tax credit
regulations, it shall be a defence to that claim that the repayment
of that amount would unjustly enrich the claimant.
32(3) Subsection (4) below applies
for the purposes of subsection (2) above where–