Dorothy's income tax and Class 4 NICs liability for 2016-17 was £ 24,600, of which £600 was deducted a t source. Her liability for 201 7-18 is £ 28,000, of which none is deducted at source. She mad e a first POA in respect of 201 7-18 on 27 February 201 8 and a second POA o n 12 Septem ber 2018. She also made a balancing payment for the year on 21 February 2019. All of her payments were for the correct amount.

(a) Calculate the amount of any late payment penalties payable by Dorothy in relation to 2017-18.

(b) Assuming an interest rate of 2.75% per annum, calculate the amount of any interest payable by Dorothy in relation to 2017-18.