payment towards following year

Hi, never quite understood the payment towards next year, for the last couple of years I have had a payment which indicates it is about 2k put onto the following year, do you add that you paid toward next year to the next return or is this factored in automatically? I have not done added these and I know on 2 previous returns I have paid to the following year. both have been paid but now I am wondering where that money is in the great abyss. so do I need to call HMRC? or can I find the amounts and amend on latest return? or is it automatically factored in? I'm so confused! can anyone help me? thank you for reading

Hi thebeesknees,
If you made payments on account to your Self Assessment account then these are not shown on your Self Assessment tax return or the resulting calculation. The payments on account will be set against the balance calculated on your statement of account automatically.
Thank you.