AUDI'S ever-expanding range was augmented by a couple of hatchbacks a few years back, with the aim of giving saloon buyers the chance to plump for something just a little bit different.

The A5 and A7 Sportbacks have proved popular, though the smaller A5 is a more familiar sight on British roads.

They're both sleek and sporty looking vehicles, the A7 more so due to its larger dimensions.

Although to my mind it still seems like a pretty new model the A7 had a mid-life makeover this year, with revised engines, refreshed styling, some new technological features and simplified new trim levels.

Black Edition is the new top-of-the-range trim option with S line and SE Executive sitting below it.

A rival to the Mercedes-Benz CLS, the A7 isn't a cheap car and certainly sits in the executive bracket, with an entry-level model costing £45,875.

That model features a 3.0-litre diesel engine and there are also two more powerful 3.0-litre diesels. Power ranges from 215bhp to 315bhp.

The entry-level lowest powered diesel offers much when it comes to delivering reasonable running costs. Known as the 'ultra' it emits just 122g/km of CO2 and manages to return 60.1mpg on the combined cycle. Pretty impressive for a car that is still pretty potent and has a top speed of 149mph and a 0-62mph sprint time of 7.3 seconds.

So, just how much better is a twin-turbo 315bhp Black Edition model? An additional £13,000 odd outlay will get you a car that goes faster and offers four-wheel-drive, as well as plenty of extras in terms of technology and creature comforts.

It tops out at 155mph and will take you from 0-62mph in an impressively swift 5.2 seconds.

In truth this has to be one of the swiftest, smoothest and refined diesel cars I've yet driven. You could also be forgiven for having to open the filler cap just to check it is actually a diesel, largely as the noise it makes is very un-diesel-like.

I'd imagine Audi's engineers spent quite some time working on an engine note that is music to the ears and in all honesty would probably satisfy even the most fussy petrol purist.

It ensures this diesel really is great fun to drive and its four-wheel-drive capability offers added reassurance. This A7 Sportback certainly offered the kind of driving experience to match its sporty styling.

While at 162g/km the 315bhp diesel's emissions might be noticeably higher than the ultra it still offers reasonable economy, with a combined cycle figure of 46.3mpg and even when driving it in a more than spirited fashion there was little discernible fuel gauge movement.

In truth it's hard to imagine needing to have more power at your disposal but if indeed you do then options are there. The S7 offers a 4.0-litre TFSI engine while orders are currently being taken for the RS7 fitted with a 552bhp 4.0-litre TFI which boasts a 0-62mph time of less than four seconds.

Performance-wise the other petrol engine option, a 328bhp 3.0-litre TFSI, is roughly on a par with the highest powered diesel though it actually has a marginally slower 0-62mph sprint time.

Styling upgrades on the A7 are minimal but include the addition of Audi's single frame grille, new tailpipes and changes to the bumpers.

Even standard models come pretty well-equipped, with electrically-adjustable, heated leather seats, parking sensors, a powered boot lid and MMI navigation.

SE Executive trim includes all-weather LED headlights, 19-inch alloys and four-zone automatic aircon, while S line and Black Edition models offer 20-inch alloys and Matrix LED headlights, which have been designed to maximize visibility and reduce glare.

Needless to say there are plenty of optional extras too and this model featured a fabulous Bang & Olufsen sound system characterised by a couple of quirky flying saucer-style speakers that pop up from the dash when you start the engine.

The A7's interior doesn't seem to have been extensively altered but suffice to say it's as sumptuous as ever.

Audi is still setting the pace when it comes to cabin comfort, exemplary switchgear and all-round sophistication.

Though it has a conventional rear bench, the A7's layout is as a four-seater. There's room-a-plenty for rear seat passengers, a big boot and hatchback versatility too.