Hi Lee,
This depends on what it is you wish to correct on your National Insurance record.
If it is for paying gaps in your record please see information at the link below
Voluntary National Insurance
If the correction is not regarding paying for gaps please write to us at the following address
PT Operations North East England
HM Revenue and Customs,
BX9 1AN
Or contact our helpline 0300 200 3500 Monday to Friday: 8am to 6pm
Closed on Saturdays, Sundays and Bank Holidays.
Thank you.