Awaiting Payment Reference Number

I am employed (PAYE). I have never registered for Self Assessment as I have never needed to. I do not have a Unique Taxpayer Reference. I have Capital Gains Tax to pay on shares sold. As this is to be a one-off, I submitted my information via the Real Time Transaction service. This was on 1st November 2024. I have yet to receive a Payment Reference Number from HMRC. Payment is due by 31 January 2025. What do I do if I do not receive a PRN in time? From what I understand, if I go down the Self-Assessment route, I must submit and await a response from HMRC to obtain a UTR. I would rather not register for self-assessment as declaring income other than my PAYE will not happen in the future as my understanding is that once you register for Self-Assessment, you need to file annually, even if you've nothing to declare. Even if I did have to go down the Self-Assessment route, what if I did not receive my UTR in time to make payment for 31 January 2025?

Hi ,
 

If your gain arises in the tax year 2023 to 2024, then by reporting the gain using the realtime transaction service before 31 December 2024, means there is no requirement for you to declare this on a self assessment tax return .  My colleagues will write to you in due course, providing a payment reference and details of how to pay the tax. Thank you .