Thanks mate! I've just had a 75,000km service done to the car and ford replaced a seal of some sort in the rear diff... 3 weeks later my diff was starting to whine like crazy, rung ford up they told me to bring the car in and it turns out the seal they replaced wasn't installed properly and the car had been leaking diff oil for a few weeks. Diff was obviosly rooted so they replaced it free of charge and I also got them to do the diff bushes (free) so after all that I'm hoping it will be centred.