So my Mazda 6 came back to me after they checked the chassis setup and found it not to be straight. Argh. No wonder the car has been driving like a dog. Oh well it's straight now and dives very well again. I've only got one niggle left and that's the clutch biting point. It seems to be at the very very top of the pedal movement. This is quite disconcerting as you think that the clutch has not engaged and it has. I might ask them to adjust it during the week, and see if this helps.