You don't need it.
It's primary purpose was to hold weird ratings that were available/required to fly certain non-EASA aircraft. I can't remember exactly what aircraft or ratings needed it but a bog standard EASA PPL(A) with an SEP rating is good enough for most of us. Many of us ticked that box when 'converting' to EASA, mainly because at the time it was free & how often do you get something from the CAA for free? The result is I now have three licences, a 90's era CAA PPL, an EASA PPL & another CAA PPL. In reality I only use the EASA PPL & only bother to get the EASA PPL signed when revalidating my ratings. Once the UK leaves EASA your UK issued EASA PPL(A) will become a non-EASA ICAO compliant UK PPL(A).