Hi, I have done it!
I used the "Blaupunkt calculator v1.0" from https://carradio.wordpress.com/
In the Serial number boxes, I put in the first 4 numbers from my radio code 2,3,4,6 then there is a grey X, so I ignored the 3, then typed in 1,9,5,8,2,2,2. Then Pressed Calculate!
It gave me...