Hello, for a few months, I found out that my birth date is incorrect in the HMRC system. I discovered this because I tried to log in for the first time on the HMRC website, and it didn't work. I sent my passport and all the details to correct the birth date around the end of October. I waited until now, and yesterday I called HMRC to find out if the change has been made or not. They said it takes approximately until March 7th.
Now my question is: Is there any method to find out the incorrect date on my HMRC details? Because I urgently need to obtain some proof from there, and it's a very long period until March.