SELLING more than a million models is a testimony to the appeal of Mercedes' baby SUV.

Baby, is perhaps the wrong term. The smallest in the range, it is far more than a pumped-up A Class, on which it is based.

With its muscular stance, but still coupe-like lines and distinctive three-pointed star of Mercedes, silver roof rails and 19-inch, five spoke alloys, it never failed to attract attention.

This latest version is a bit higher and a bit shorter than its predecessor, but all models are well equipped and goodies increase as you move up the range with this range topper featuring leather, heated and powered seats, 64-colour ambient lighting multi-function steering wheel and high-end sound system.

Like all Mercs it hosts myriad gadgets and gizmos, not least its clever MBUX entertainment system which now uses the latest augmented reality software and a comprehensive range of safety kit. It also features highly efficient and frugal petrol and diesel engines and other cutting edge technology.

The interior on this range-topping model is pure executive quality, with piano black and soft touch finish throughout.

Five round ventilation units are meant to offer a turbine look, and trimmed in chrome, are a classy touch. The centrepiece is a 10.25inch touchscreen which is the brains of the car, connected to a touchpad on the central console.

Unlike some touchpads, this one is not jerky and works well, operating key features like sat nav, infotainment and connectivity for smartphones. It also houses the reversing camera.

On this AMG model another 10.25 inch display merges with the touchscreen to provide a cockpit style and to deliver key driver information.

The standard MBUX connectivity system uses voice control. It can be individually configured with the aid of a range of options for configuring screens and graphics and sat nav with augmented reality and learning software.

For this to work, the camera in the roof console behind the windscreen records a video image of the surroundings. This, in turn, enhances the system with helpful navigation information. Indicator arrows or house numbers are automatically superimposed on the image shown on the media display touchscreen.

The GLA features two petrol and two diesel variants, with this model featuring the two litre, 190bhp diesel engine, mated with an eight-speed, dual-clutch transmission.

It is an extremely lively and refined unit offering rapid acceleration, high levels of torque, 400Nm for excellent pulling power in all gears and lowish CO2 emissions. Add to this fuel consumption of around 50mpg and that's pretty impressive considering the car is carrying the extra weight of the four-wheel drive capability.

This diesel is a refined unit with barely any diesel clatter while acceleration is very brisk, the car hits 60mph in just 7.3 seconds.

The increased dimensions means there is plenty of leg and headroom while the seats are comfortable and supportive, the firmish but smooth ride means passengers have a comfortable experience and despite its high stance, the vehicle always feels stable with a marked absence of wallowing on corners.

As an SUV it needs to be practical and the seating arrangements offer various combinations, while the 485 litres of boot space can be increased to a maximum of 1, 420, while the sliding rear seats offer extra practicality.

While unlikely to spend much time off road, the four wheel drive offers extra safety, with added traction in poor weather. Actually offroad, power is transferred 50-50 to each axle, giving the capability of pulling a horsebox or caravan on and off a muddy field.