I've followed this guy for years and he's helped me out countless times. He recently bought an 07 R56 S and has started The MINI Series. These videos will help all sorts of 2nd Gen owners.
This video is a How-To on battery replacement for an R56. NOTE-You may or may not need to register your battery after re-installation. I registered mine using the Carly for BMW app. You can drive the car with out registering the battery (I wouldn't advise driving it for several days) if you want to take it somewhere to have it registered.