PJ MC

In the 23/24 tax year I sold various shares. Some made gains and some made small losses, which I wished to be deducted from the capital gains on which tax was payable. All the shares were listed. I filled in the relevant boxes declaring number of disposals, total gains (before losses) and then total losses in Box 27. I also provided detailed additional information about all the sales, gains and losses on a separate sheet. I thought that was sufficient for HMRC to deduct the losses in box 27 from the total taxable gains, but was subsequently told that I should also have put the losses in Box 46 if I wanted HMRC to deduct them from the taxable gains made in the same year. Is that correct? I am retired so have no earnings and my only other income is from a SIPP and dividends. I would like to make sure that any future losses are deducted from any taxable gains but don't want to put the losses from Box 27 in Box 46 if that is for something else.