Income Tax Computation

Alfred is trying to calculate his balancing payment for the tax year 2023-24, and the following information is available:
He has been in partnership with Anne and Mary running a retail shop since 6 April 2014, but Mary resigned as a partner on 1 January 2024.
The partnership’s tax adjusted trading profit for the year ended 5 April 2024 is £228,000. This figure is before capital allowances.
The tax written down value of the partnership’s capital allowances main pool at 6 April 2023 was £10,000. The only capital expenditure during the year ended 5 April 2024 was the cost of £82,000 for refurbishing the second floor of the partnership’s shop during January 2024. The cost was made up as follows:
£
False ceiling 17,600
Display units 15,100
Tiled flooring 32,200
Moveable partition walls 17,100
82,000
The partners have always shared profits equally and continued to do so after Mary resigned.
During the tax year 2023-24, Alfred received dividends totalling £6,060, of which £720 were from investments within an ISA.
During the tax year 2023-24, Alfred made gift aid donations totalling £1,920 (net) to national charities.
Alfred’s payments on account of income tax and class 4 national insurance contributions in respect of the tax year 2023-24 totalled £20,200.
Required:
Calculate Alfred’s balancing payment for the tax year 2023-24.
(13 marks)
Note: You should take account of class 4 national insurance contributions when calculating the balancing payment for Alfred.

study hub answer= Income tax computation 2023-24
£
Trading profit (W1) 72,750
Dividends (6,060 ? 720) 5,340 1
78,090
Personal allowance (12,570) ½
Taxable income 65,520
40,100 (W3) × 20% 8,020 ½
20,080 (65,520 ? 5,340 ? 40,100) × 40% 8,032 ½
1,000 × 0% 0 ½
4,340 × 33.75% 1,465 ½
65,520
Income tax liability 17,517
Class 4 national insurance contributions (W4) 3,843
21,360
Payments on account (20,200) 1
Balancing payment 1,160
WORKINGS
(1) Trading profit
£
Trading profit 228,000 ½
Capital allowances (W2) (34,000) ½
194,000
Profit share
6 April to 31 December 2023 194,000 × ?9 over 12? × ?one third?

48,500 1
1 January to 5 April 2024 194,000 × ?3 over 12? × ?one half?

24,250 1
72,750
(2) Capital allowances

Main pool Allowances
£ £ £
WDV brought forward 10,000 ½
Additions qualifying for AIA
False ceiling

0 ½
Display units

15,100 ½
Tiled flooring

0 ½
Movable partitions

17,100 ½
32,200
AIA – 100%

(32,200) 0 32,200 ½
WDA – 18% (1,800) 1,800 ½
WDV carried forward 8,200
Total allowances 34,000
Tutorial note: Expenditure forming part of a building, such as the false ceiling and tiled flooring, does not qualify as plant. The display units and the movable partition walls are not treated as forming part of the shop building, and therefore do qualify as plant.
(3) Tax band
Alfred’s basic rate tax band is extended by £2,400 (1,920 × ?100 over 80?) to £40,100 (37,700 + 2,400) as a result of making the gift aid donations.
1
(4) Class 4 national insurance contributions
Class 4 NIC for the tax year 2023-24 is £3,843 ((50,270 ? 12,570 = 37,700 × 9%) + (72,750 ? 50,270 = 22,480 × 2%)).

I am only struggling with income tax computation. The basic band has been extended by 2400 due to a donation, but it has not been reduced by 1000 for the dividend nil rate band as I have read that it uses basic slab. Can you please explain why the reduction of 1000 from the basic rate band was not done?