Thank you for your kind replies. It’s from the Kaplan study text, and I got what it means now. The used allowances for 2022/2023 is £58,000 {2022/23 – £40,000 + 2019/20 – £18,000 (£40,000- £12,000 = £28,000 but will only use £18,000)}. And the remaining £ 10,000 cannot be carried forward to 2023/24.
If I don’t understand one thing, it’s very difficult for me to move forward. My question might be a bit silly, but I hope you understand :’).