but later also says:"Before paying any shortfall, it is important to find out if your state pension will increase once you've paid voluntary National Insurance contributions (NICs). When you've paid the shortfall, please call the Future Pensions Centre to find out which tax year will count towards your state pension
So anyway I called the "Future Pensions Centre" [*], and actually got through and they helpfully confirmed that yes, my pension will increase if I pay the shortfall (which I knew already because why else I am I doing this?...), and informed me (incorrectly, as I suspected) I'd need an 18 (?) digit reference code to make the payment with, and then they offered put me through to HMRC, which by some miracle actually happened, and HMRC said I need to use the code made up of NI number and name (details on gov.uk somewhere), and specifically:Due to changes in the law, you need the Pension Service to confirm whether your State Pension will increase if you pay any shortfall
- I need to make separate payments for Class 2 and Class 3
- Class 3 payments will take up to 8 weeks to be processed
- Class 2 payments can take up to a year to be processed
- as long as they get the payment(s) before April 5th, they will be credited
- they made a note in my file that I have informed them I am intending to make the payments
[*] I called using Skype (need to burn through the remaining credit), which basically worked fine, however sometimes the system seems to "freeze" (minutes of silence), so it took a couple of goes before getting to the muzak point; first time I got through to an operator after about 20 minutes but they couldn't hear me; second time also took about 20 minutes.
Hope this info is of use to anyone in the same situation.