Basically engine management light came on on 28 December. It went out again after a few restarts so I drove home (around 25 miles). By the time I got home the engine sounded rough and I thought that perhaps it was a badly fitted filter as I had got him serviced 2 weeks earlier. I contacted the guy who normally serviced the car, but he said that he was closed for another week. I can't do without a car so I brought the car to the main dealer as that was the only place open. They ran a diagnostic but said at that point that the alternator belt had stretched so much that they couldn't check the engine function till it was replaced. Basically all the parts they needed for my car were not items they would normally hold in stock so there was always a bit of a wait for parts. They got the car running but it sounded rough and there was no turbo boost. They checked the turbo and confirmed it was fine and tried a new MAF sensor which confirmed the old one was fine (so they removed the new one and replaced the old one). They then checked the fuel system for any leaks and found the fuel pipe was cracked so they changed that. Still running rough with no boost. They asked if any other work had been done to the car. I told them that the timing chain had been replaced end of January 2013. At that stage they had done all the cheaper options and they said that they would need to start dismantling to find anything else. Turned out that the guides on the new timing chain had failed and the timing had jumped. This was the cause of the rough running. So they replaced the timing chain (full set) and the engine run fine again. Luckily it seems that no engine damage has been done.
Then just my luck but the clutch went and I had to return him to get that changed.
With all that the car feels like a new car and seems to be running better than it's been for a good while. I'll keep an eye on the mpg. Although I was previously averaging 60mpg, I'm hoping that might improve, lol.