That might be the issue as I'm using another manufacturers Y cable as it's more flexible than the Ford one. I've ordered a genuine Ford cable to see if that works. At least if it doesn't I can take it back. I would have thought though that a Y cable for an iPod would work in any car with USB and 3.5mm jack but it's maybe not the case.
I ordered the Y cable yesterday and it arrived today at the dealer and, yeah, it works. I love the way you can move tracks on the steering wheel and that the song title, track number, artist, album, etc are displayed on the multifunction display. Now just to resolve the best place to put the iPod as the cable is a tad too short or a tad too long.