You're the sort of garage to steer clear of then!!! ^^^^
A friend of ours has a Vauxhall garage and if someone trades in something like a Clio, Fiesta, Focus etc they get sent to auction and not because they have anything wrong it's just that they prefer to sell Vauxhalls!
Also most garages don't want cars over a certain age or mileage and will send them to auction and not because there's anything wrong at all!
Just have a good look over and under it.... chances are, the majority of cars are OK, especially as they are much cheaper than from a garage!