(a) Warren's liability to income tax and Class 4 NICs for tax year 2019-20 was £17,200, of which £14,500 was paid via PAYE.

(i) Compute his POAs for 2020-21 and state the dates on which these fall due.

(ii) Compute the balancing payment for 2020-21 and state the due date of payment, assuming that Warren's liability to income tax and Class 4 NICs for 2020-21 is £19,300, of which £16,100 has been paid via PAYE.

(b) Diana's liability to income tax and Class 4 NICs for tax year 2019-20 was £3,400, of which £2,500 was deducted at source.

(i) Compute her POAs for 2020-21 and state the dates on which these fall due.

(ii) Compute the balancing payment for 2020-21 and state the due date of payment, assuming that Diana's liability to income tax and Class 4 NICs for 2020-21 is £11,400, of which none has been paid by deduction at source.

Ignore Class 2 NICs and capital gains tax.