Happens on some cars, happens with some tyres more than others. Get the alignment checked on the rear axle, very few poeple bother, on some cars its shims, on others its easier, on some its impossible.
Thanks for the response .
No the tyres are Continent Conti Sport .
I wouldn't know if the suspension has negative camber.
The VW main agent says that it is common on the CC but cant(won't ) do anything about it , didn't suggest having the suspension checked, said to try changing tyres back to front,or buying new tyres and have the same problem after 19k!!