Sorry for taking ages to reply.
First thing's first, disconnect the negative terminal from your cars battery.
There's my wire.
Theres where it lives. (In the blue mini plug)
That's the negative wire connected up to the ground wire (bottom right wire in the white plug) on the power plug of the ISO radio connection. I took the pin out of the plug and prised the crimp slightly, slotted the wire in and re-crimped, the tape is just adding a bit extra support.
The positive wire is a bit harder. I started by cutting another piece of insulated wire, like in the first picture but this time about 500mm, and joined it to the positive wire of the iPod cable using one of the connectors I'm holding. (Can't remember which I used, again the tape is only there as extra support as I didn't have any heat shrink)
Take off your gearstick gaiter and move the gearstick into 2nd gear. (No reason other than it makes it easier to get your hands in) Feed your newly cut long wire down behind the radio until it finds its way to under where the cigar lighter is. It might be easier doing the other way round but it will get there I promise.
Once the wire is in place, unplug the connection to the cigar lighter (clip next to my thumb in pic) and remove the middle pin from it, (3 lugs under the brown thing in pic, push or prise slightly on one to release the wire) then same as before, prise the crimp and slot the wire in a re-crimp. Insert the wire into the plug again and connect it back to the cigar lighter.
There you have it, radio set to changer and it's even charging while it plays