I think it looks more like this:
Total earnings, including projection to end of tax year, £53,800
(Less pension of £3,500)
Taxable pay £50,300
(less personal allowance £12,500)
Tax is due on £37,800
The first £2,085 is taxed at 19% = £396.15 tax
then £2,086 to £12,658 (£10,574) @ 20% = £2,114.80 tax
£12,659 to £30,930 (£18,271) @ 21% = £3,836.91 tax
£30,931 to £37,800 (£6,869) x 40% = £2,747.60 tax
Total tax due for year 20/21: £9,095.46
(Less tax paid to date £7,000)
Tax due for remainder of year: £2,095.46
That's so different from your figures, OP, that I'm really doubting myself, especially as I was too lazy to stir myself from the sofa to get a pen and paper, which is always a bit risky for me.
I look forward to being corrected!
I got the rates & bands info here www.gov.uk/government/publications/rates-and-allowances-income-tax/income-tax-rates-and-allowances-current-and-past
When I'm working, I have access to a benefit calculator that is very good at working out net pay, but I'm not sure if it works for Scotland.
PM me if no-one else comes up with a definitive answer, and I'll check it out for you on Tuesday!