From personal experience, I'd be a bit wary of Car Giant.
Went there previously to view a car, all looked fine and lovely online. When I went down there to see the car in person, I noticed they'd stuck a sticker on the speedo saying they cannot be held responsible if the speedo has been tampered with or readings incorrect etc, something along the lines of that anyway. It was also on one or two of the other cars that were there! Put me right off!