Not sure if this is the right place to post this.

I have just been into Halfords and picked up the Autoleads adapters for the Focus wiring so that I can run my Sony headunit. This little lot cost me just under £50 which seemed a little steep to me but still cheaper than buying a new Ford headunit, as mine has had it! I was hoping that this lot would be able to run the factory fit sub and amp that was installed in the car when new but after sitting in the car and playing around for half an hour I have decided they don't!

Does anybody know if there is such an adapter lead or will I need to think about refitting the old headunit and taking the leads back?