I am trying to fit a new battery to my 1998 audi a4, but how the hell do you get the old one out!!!?? On the right hand side of the battery there is a nut facing you that you can just reach, but it is impossible to turn with a normal spanner. It looks like its attached to the black plastic thing at the back and I'm not sure if you have to take this off at all but it seems like its holding the battery in place?? Could anyone please shed some light on what i need to do first to get the battery out and if i need any special tools or anything? any advice would be much appreciated thanks!