Where to send payment to pay gaps in NI class 2 abroad

Hi HMRC, I have received confirmation that I can pay the shortfall of class 2 NICs 2006-2024 (18 years). I am anxious to make this payment as an all in payment in one lump sum. I now live in Ireland and will be 66 in January. I was going to make the payment from my UK Sterling account by cheque but I am not sure where to send it as one address is HM Revenue & Customs National Insurance, Contributions & Employer office BX5 5BD or HM Revenue & Customs, National Insurance Contributions & Employer Office BX9 1AN or do I send it to the address on the letter PT Operations North East England BX9 1AN. I just want to have it right as I don't want the cheque to go astray. I know to put my NI Number+IC+surname+initals on back of cheque. Thanks Dolly

Hi Bernadette,
If paying your voluntary National Insurance contributions by cheque, please send it to the following address with a covering letter:
National Insurance Contributions & Employer Office,
HM Revenue & Customs,
BX5 5BD,
United Kingdom.
Thank you. 

I am trying to pay voluntary contribution class 2 which I have received confirmation of which years and how much is due. However, when trying to pay with bank transfer to the sort code and account number provided, HMRC are insisting upon an 18 digit number starting with 60. It is not possible to enter the syntax requested, i.e. NI Number+IC+surname+initals. Is it possible to pay by bank transfer or do you suggest I send a cheque? Thanks for you response

Hi Spellers,
If you do not have a 18 digit reference you can not pay via the gov.uk website.  
You can still make a payment through your bank using your NI number and surname and initials.
More information can be found on www.gov.uk
Pay Class 2 National Insurance if you do not pay through Self Assessment: Make an online or telephone bank transfer - GOV.UK (www.gov.uk)
Thank you.