If you're a UK resident attempting to get a London ULEZ exemption, you are not going to get one by providing date of manufacture information from a random website like
realoem or any other. You'll need a certificate from
BMW verifying the date of manufacture and with it, you'll need to navigate the serpentine route of registering your Brick as a historic vehicle that is 40 years old or older. The process is laid out on a couple of UK government sites, like
this one and
this other one. You'll note on one of those sites that the exact month of manufacture doesn't matter. What matters is that the motorcycle was manufactured before 1 January 2025. The certificate from BMW will verify that.
Have you explored
those sites?