It's quite normal for car supermarkets (and, indeed, any car dealer) to source cars from auction. As with any year-old car, I'd be a little concerned about what it's been used for. It's unlikely to have been owned by a private owner for a year, so is likely to have been a fleet or even a hire car. It might even have been used by a driving school, although the mileage doesn't sound particularly high. That said, if it's been serviced correctly this might not be an issue - and you'll be making a big saving over a new car.