Mine (V70 not XC70) also pulls slightly left; not all the time, which has always made me think it was just camber?
I've had it 6-7 years (from 60,000ish to 132,000 miles now), several sets of tyres, various bits of suspension replaced and refreshed over the years, still always pulls left.
I just live with it, it's only a big wallow-y family bus / work-horse, it'll never be a precision driving tool, not worth spending time and money trying to 'fix' it...
