Thanks for the post that's useful.

Not sure how easy it will be to contact the owner as I purchased it through a garage, however I've had a look in the boot and it appears that there are no new cables that have been run to the boot.

Therefore I'm guessing the iPod installation wires up to the front sat nav unit somehow. Does that narrow it down to any specific units? Does anyone have an installation guide for what unit it could be?

Many thanks