The radio is definitely post 09/2002 (the car is 2006, but I checked the build date on the radio anyway just to be sure). So it may well be a dud cable. Thing is I'm reluctant to fork out for another one, especially an OEM one, only to find out it doesn't work either and the issue lies elsewhere.

It would be a lot simpler to buy an aftermarket head unit... why do they all have to look so crap.