Capital gain offset loss

By trading stocks, I made a loss £50000 last year and gained £10000 this year. To offset this year gain by last year loss, please advise if I should put '£10000' in the box 45 of SA108 (Losses brought forward and used in-year) or elsewhere. Also, how can I notify HMRC that there is still £40000 eligible for offsetting future gains? Many thanks.

Hi Ben716,
If you are referring to the 22/23 tax tax year, your gains are covered by your annual allowance so you would not need to put a figure in box 45.
You can put the details of your losses, a full breakdown would be required - on the additional information section so that HMRC are aware that you have these losses to be carried forward for later use.
Thank you.