Apologies for not coming back as I bought an a6 at the weekend instead and maybe you should of noticed this "New Poster" posted this question over a month ago and had zero replies until this week. And I was checking every day actually on here, up until that car sold which was weeks ago, but I got the impression the forum wasn't used much so got advice on another website.
Saying that the advice on the other site wasn't as detailed as yours. The car sold before the people on the other site even responded so wasn't meant to be but to be honest, I found the a6 far superior.
The other car was irish whereas the a6 was bought new from England and only driven on Irish roads. Both had full dealer histories, but the a6 is a 2012 with only 63k miles so is gleaming. The a5 was sold buy audi sligo to another crowd and I confirmed this when I rang audi sligo.
Both cars had a timing belt and the a5 had never been changed which I was very concerned about, where as the a6 was done by the dealer I bought it off, with proof so was good. I'm slightly concerned about the clutch as heard they can go around the 70k mile mark by a mechanic but so far feels really nice.
While I would of preferred a 2013/2014, I saved a fortune with a 2012 and at least when I go to trade in about two years it will still have relatively low miles so might get a good deal for it.
Had no intentions of buying an a6 but when I drove this there was no comparison I felt with the a5. The a5 might look nicer but for comfort, lack of road noise, and the enjoyment of the big cabin for the long commutes I do the a6 was just far superior and I absolutely love getting into it every day🙏.
