Incorrect Date of birth on HRMC system

Hello I have been trying to log into my tax account via gate away id and have been getting message that my details does not match and it s been months like this. Yesterday, I called HMRC for some tax code clarification and have been told that my date of birth is incorrect on the system and i need to send document to get it corrected Please can I kindly be guided about the process, where to send the document and does the original driving licence will be sufficient ? and should i include a signed return post envelope in the post as well for return of the document and how will be notified once the changes have been made? I will be very grateful for the response thanks

Hi,
If your date of birth is incorrect you will need to submit evidence of your actual date of birth. Please include your National Insurance number, and, or UTR on the first page of the letter, your full name and your full address including the postcode. Please ensure you sign the letter.
The evidence you provide must be an original document or certified copy. We accept the original document or certified copies of a birth certificate, passport, we can accept even if out of date, full driving licence, not a provisional licence, or an ID card, all parts of the ID card must be copied. 
Please send this information to: 
PT Operations,
North East England,
HM Revenue and Customs,
BX9 1AN
Thank you.