(1) In this Chapter -

"accountable person" has the meaning assigned to it by section 521;

"appropriate tax", in relation to a relevant payment, means - (a) where such payment does not include value-added tax, a sum representing income tax on the amount of that payment at the standard rate in force at the time of payment, and (b) where such payment includes value-added tax, a sum representing income tax at the standard rate in force at the time of payment on the amount of that payment exclusive of the value-added tax;

"authorised insurer" has the same meaning as in section 470;