switching to remittance basis for past years

Hi, I have been filing tax returns for last 4 years (2019/20, 20/21, 21/22. 22/23) myself. I have recently figured out that I should have checked the remittance basis flag for the global income. I have not remitted any money so far. Do I need to use the WDF (Worldwide Disclosure Facility) and resubmit the past years tax calculations or Can I amend the tax returns using the authorised tool to resubmit my tax returns as Remittance Basis? Please suggest. thanks, 

Name removed admin .

Hi Sam,
You would need to write in giving the amended detaiils for each year to:
HMRC PAYE & Self Assessment
BX9 1AS.
Thank you.