HMRC confirmation of no personal income tax owed

I moved from the UK to Slovenia in 2022, and in order to set up a business here, I must provide formal explicit confirmation from HMRC that I do not owe any income tax in the UK. The document must be legalized (apostille), and have a wet signature of an HMRC representative. I have managed to procure such a document in February '24 via an online chat with a very helpful HMRC customer service advisor, but the document has since lapsed due to being more than 60 days old. No agents I managed to speak with on the phone today managed to understand my request, or advise on how to proceed. How do I procure such a document / letter again from HMRC? All it needs to say is that I do not have any outstanding income tax due, and have a name / surname, plus signature of an HMRC employee.

Hi,
You will need to apply for this in writing and send it to HMRC PAYE & Self Assessment BX9 1AS.
Thank you.

I have the same issue. I posted my request to HMRC early September and have proof it's been delivered. However, I am yet to receive the document requested. When can I expect it to be sent? Unfortunately, when I called nobody was able to provide any advice, or even confirm the receipt of my request.

Hi,
You can find out when you can expect to receive a reply form HMRC here:  
Check when you can expect a reply from HMRC
Thank you