Audi is working on its next-generation Q7 and spy photographers captured the new model undergoing testing in Germany.Spy images show larger fenders and shorter front overhangs. The Q7 is expected to be a lot lighter with the SUV set to lose about 400kg. Image gallery: Audi Q7 (Spy)NEW SUV PLATFORMThe Q7 will ride on the Volkswagen Group’s third-generation SUV platform, derived from the car-based MLB architecture. It will spawn both the Q7 and a Bentley SUV due in 2016.The engine range will include 3.0 and 4.0 TFSI units and a 3.0 TDI. A plug-in hybrid model is also due.