Paddy Murphy

I want to make payment(s) for missing years. However I do not want to pay all the missing years. I sent the form CF83 in February 2023, completing the direct debit form to enable HMRC to deduct the payment from my UK bank account. I received a letter to say I should make the payment manually from my online banking. However when I make the payment how do I inform HMRC exactly which years the payments are for? The reason is the increase in pension from buying back missing years is not equal. As an example if I buyback 2017 my pension will only increase by £8 per year so spending over £800 is pointless. Some of the years have equal prices to buy back but do not have equal increase in my pension so I do not want the payment I send to HMRC being applied to years that bring me virtually no increase in my pension