Thanks for your comments- your input is much appreciated.
I have a BMW 325 at the moment and fancied a change / something slightly bigger to get the kids in. Audi seemed to be comparable and (slightly) cheaper, and I thought that a high mileage model may fit the bill. Thought their engines were good for 200k miles before they give up the ghost.
I have also been keeping my eyes open for a 5 series diesel, but they always seem dearer. Guess that's because they keep coming out top in all of the surveys.
There's a 2007 A6 with 126,000 miles over in Lpool for £6800, but when I went to see it, it had no drivers door lock (everything else perfect). They said they were getting a replacement from Audi, but it had to come from Germany. Four weeks later they still haven't got it. Fishy?? What do you think?