CAR Ipod Interface AUX IN Adapter FIT BMW Mini ONE Cooper E39 E53 X5 E60 E61 12P | eBay

Ok, so basically the back of the plug connects into the spare bottom right port in the 'headunit's back - so you don't loose any functionality. The aux is simple, but the above link is for iPod etc to allow for charging (extra wires). I get one is a ground wire, but that red wire? where does that go? Where do two of the ends go? I'm assuming it will come with one end connected, but if not..??

They've said the other wire is to go to 'ignition'? What?

I can only assume there is a port that it needs to plug into either in the stock plug or somewhere else?

 

When connecting electrical stuff, there's always a live wire and a neutral/ground wire, or a positive wire and a negative wire, or a red wire and a black wire, or a left speaker wire and a right speaker wire, etc

It all means the same thing; they just have different names based on what they are being used for.
Wire 1 takes electrons one way.
Wire 2 brings them back.