incorrect national insurance number

My employer, the NHS, has been using an incorrect national insurance number since 2008, they have only just changed it to the correct number so the number on the payslip and latest p60 is now correct. The incorrect number was similar to my correct number, the second letter was wrong. How do I go about correcting my national insurance record from 2008-2023? Should my employer do this? or should it be me. I have most of my payslips and P60's going back over 30 years. thank you for reading

Hi,
Please if possible can you set up a Personal Tax Account to check your national insurance record.
It may be that your National Insurance Contributions have been going to your right National Insurance Number and it has just been printed incorrectly on your payslips and P60s.
You can check your national insurance record on your PTA. Please find the link below to set up a PTA.
Personal tax account: sign in or set up
Alternatively you can call the National Insurance Enquiries Helpline
If you still believe after checking  your PTA contributions have gone to the wrong National Insurance Number please could you send in letter to the address:
Individual Caseworker
PT Operations North East England
HM Revenue & Customs
BX9 1AN 
Please include the following information:
•    your employers name and address
•    your employers PAYE reference number, if known
•    the date you started their employment
•    the right and wrong NINO
•    enclose copies of payslips or P60s for period(s)
Thank you.