Couple of things. Firstly, that's trade and no where near what you'd get trading in or selling privately. Secondly, Shaks Cars are notoriously overpriced. I mean, massively overpriced and they'll never get that unless some mug walks in. Also beware that they apparently clock their cars (an owner over on VWROC confirmed this!). Finally, there's plenty of better specced and cheaper cars to go for.
Hey, I hope you prove me wrong. As an existing owner I want residuals to be super strong. But I maintain a decently specced, average mileage car will cost you £10k over two years.