Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
So long as the capital losses were reported to HMRC within four years of the end of the tax year in which they incurred, then you can use them against capital gains made in the future. There is no time limit by which they need to be used.
I hope this helps but let me know if you have any further questions.
If you still have the calculations of each loss, I'd submit those with the tax return for the tax year in which you wish to use the losses.