I am a British citizen, I have an appointment tomorrow morning at our city's Stadthaus to begin my German citizenship applcation, but due to me being disorganised /stressed /being a muppet, I have only now realised that I do not have any of the most important pieces of documentation required so they can begin processing me. I still need to take the Einbürgerungstest and get official copies of marriage certificates, as well as pay for the whole thing! I want to retain my UK passport. Assuming I can get all my Unterlagen handed in before the end of the year, what are the odds they will allow my to have dual citizenship?