No pick and choose which years you want to pay and phone HMRC to inform them of those. They will flag up those years on their system while waiting for your payment which when received will be credited to those years.
There is a deadline of April 2025 fast approaching. I believe that represents a cut off for new applications but possibly not for actual payments. Nevertheless I would pay the earliest years first as the normal rule when back paying is that you can only back pay for the previous 6 years.