Guidance Needed on Reporting ISA Overpayment and and Capital Gain in 2023-24 Tax Return

Dear HMRC, I am writing to seek clarification on how to report an error I made with my ISA contributions during the 2023-24 tax year. On 9 October 2023, I deposited £20,000 into a cash ISA with Bank A. Later, on 6 March 2024, I inadvertently deposited an additional £1,500 into a stocks and shares ISA with Bank B. In May 2024, I realised that I had exceeded the annual ISA allowance of £20,000 for all ISA types combined. To rectify this, I sold the investments in the stocks and shares ISA and withdrew the funds, amounting to approximately £1,575, on 16 May 2024. This withdrawal included a capital gain of £75. I need to file a self-assessment tax return for the 2023-24 tax year and would appreciate your guidance on the following points: 1. Should I include the over-contribution in my 2023-24 tax return, or should it be reported in the 2024-25 tax return? 2. Should the capital gain of £75 be reported as part of my capital gains for the 2023-24 tax year? Thank you for your assistance.

Hi,
HMRC will contact you in due course regarding the excess ISA payment and what to declare.
The CGT falls into 24/25 tax year.
Thank you.