CGT shares loss what’s needed in letter

I sold some shares last year and made a loss. I know that I need to write to you with the details, but cannot find anything that says what should be in the letter. I assume it’s NI number, date amount and cost of shares, and the date and price they were sold at. Do you need to know anything else, e.g. company name of the shares, which share dealing service I use etc? Thanks for your help.

Hi,
If not in Self Assessment to comlete a tax return, you can send a computation of how you have arrived at your loss. Each tax year must be separate.
Ensure your National Insurance number is included to allow us to trace your record.
Thank you.