Made a mistake with my tax residency on past self assessment, how do I correct the record?

I left the UK in 2016 and have not returned since, but before I left I rented out my house (managed by a lettings agent), which is my only source of UK income after I left. This income is not high enough to be taxed, but high enough to need to fill out self assessment. Because of this, I continued to fill out self-assessment at the request of HMRC on the HMRC website every year to report my rental income after leaving the UK. However, due to my inexperience I was unaware until today that non-UK residents were not supposed to use the online form, and instead were supposed to submit a paper form or third party software along with a SA109 form. So I think I mistakenly declared myself as a UK resident since 2016 by using the online form. I want HMRC’s record of me to be corrected and state I’ve been non-UK resident since 2016, but I’m not sure how to do this. I already tried changing my address on my HMRC tax account but I could not do so because it says the address is earlier than the one I currently have (I added a relative’s address on there to receive my letters from HMRC after I left the UK). Should I fill out a (very late) P85 online and if so is that sufficient? Do I need to contact HMRC separately in writing as well to inform them I want to correct my self assessment forms since 2016? Note I’m not expecting a tax refund or having to pay more tax from this because the rent I received is below the taxable threshold. The part I care about is correcting HMRC’s record of my tax residency status.

Hi,
It is too late to amend your tax returns for 2021 to 2022 and earlier, so for those tax years you will need to write to: HMRC at:
H.M.Revenue and Customs Self Assessment
BX9 1AS,
to confirm that you are not UK resident for those years, but you are entitled to claim personal allowances (you will need to look at the guidance notes for supplementary page SA109,  boxes 15 and 16 at:
 Residence, remittance basis etc (Self Assessment SA109)
for the reasons that you continue to qualify for personal allowancs.  
For tax years 2020 to 2023 onwards, you can download the relevant SA109 page and submit it to the address above.  Going forward, you will either have to submit a SA return in its entirety on paper or by buying a commercial tax return that allows you to submit online.
You should note paper tax returns must be submitted by 31 October each year, to avoid late filing penalties and interest charges.
Thank you.

Thank you for your answer. If I just want to amend my tax residency to non UK resident for previous years (so since 2016-2017), can I just write a letter to HMRC explaining the situation, rather than submit multiple SA109 forms some of which are no longer available? What information should I include in the letter? Should I submit a P85 as well, or is there no point?

Hi ,
 

Where you cannot access and submit an SA109, please write to us as described above, confirming all years affected, and detailing the issue as you've previously described . Thank you .