THERE used to be a mindset that drivers of large cars preferred traditional saloons with four doors and a boot at the back.

That is if they weren't behind the wheel of a big SUV like a Range Rover or BMW X5.

But times they have been achanging and the trend towards the more flexible format of hatches, fastbacks and five-door coupes has spread from the mid-market sector to prestige models.

One of the marques that was ahead of the curve is Audi which first introduced the stylish A7 Sportback range a full decade ago. Sleek, roomy enough for five and designed with a sporting edge it has engaged with families, business people and outdoor types alike, all won over by the versatility and blend of luxury with a sort of everyday practicality.

Not that the A7 is particularly capacious for absorbing huge or awkward-shaped loads - there are many estate cars that can pack in more stuff.

But its secret lies in being an appealing stepping stone between the traditional notchback and a more utilitarian estate.

With a range of petrol and diesel engines, we went for the popular 50 TDI which comes with a 3.0-litre, V6 turbo diesel engine - not sure how the 50 tag was arrived at - giving it the sort of clout that many a sports car would envy. It's expected to account for the majority or British orders.

Matched to an eight-speed Tiptronic automatic gearbox, it sets out to blend ease of driving with strong performance, refinement and reasonable economy. With a sprint to 62mph being accomplished in under six seconds and a max of an electronically limited 155mph, few would criticise its pace.

Together with a luxurious and well appointed cabin which cocoons its passengers from both mechanical intrusion and outside noise, the big Audi is a clever compromise between the somewhat staid A6 and its estate car brother, the Avant.

The second generation A7, launched last year, was redesigned from the ground up boosting refinement, performance and economy.

With fat, huge 8.5J 19-inch alloys shod with low profile tyres and quattro four wheel drive, it's hardly surprising that it corners almost as if on rails. Shame though, that few messages from the road are relayed through the steering wheel to the helm.

Bags of torque - 457lb/ft to be precise - mean that mid range thrust is massive and near instantaneous via the excellent auto box. Engine noise is well isolated but when you do hear it, under hard acceleration, it's a harmonious roar rather than a diesel rattle. A V6 oil burner is so much better than a four-pot.

There are unlikely to be many complaints at the fuel economy which in our hands worked out at 34mpg, considering the huge depths of available performance.

Ride at low speeds over average surfaces can feel a tad nervous and fidgety, but as the pace mounts so does the composure improve, making the Audi feel at one with the road and securely planted.

The interior is useably stylish with a fashionable slant and finished with typical Audi quality. Double touchscreens, few switches and buttons and a simplicity of design add to the uncluttered approach.