Re-activating sole trader business - increase to payments on account needed?

Hello, I have already filed a return for 23/24. I was a sole trader but ceased this in Sep 2024 to move on to a PAYE contract. I completed the cease trading form as part of my 23/24 return. My PAYE employer then later closed their business, meaning I was unemployed. I resumed self-employed sole trader work in Oct 2024. My questions are: How do I re-activate my sole trader status Do I do need to this as a new business? It has been a calendar year since I was last self-employed. Most importantly: Do I need to make payments on account for this work? And if so, how do I adjust my last return to do this. At the time I ceased trading I did not expect there to be any opportunities to for self-employed contract work in my specific field and assumed I end up in PAYE work elsewhere. Thank you.

Hi,
You would need to contact our Self Assesment team to make them aware of your change of circumstances. They can reactivate your self assessment record.
Self Assessment: general enquiries
Thank you