CGT - box 47

Hi, my query relates to how to use box 47 properly on the SA100. I am just using some made up numbers, to see if I understand the procedure correctly. Say in return 4/22 I had £5k in box 47 (Losses available to be carried forward) In return 4/23, say I had losses in that year of £20k and entered this in box 19 (Losses in the year). What should go in box 47? Is it £20k or is it £25k? If in return 4/24 I had no CG's at all. Do I need to put anything in box 47? Or do I leave it blank and HMRC would know that I still have the amounts declared in 4/23 to carry forward? Thanks.

Hi D C,
You can carry your unused losses (including 
‘clogged losses’) forward to later years.
Enter the total amount that is to be carried forward.
Thank you.