It all used to be so simple. There would be a 1.3 GL, a 1.6 GLX and a 2.0 Ghia. Everyone knew where they stood in the pecking order, and there were even helpful badges on the boot lid to tell all and sundry in which rank you stood.

Now? Now it’s all but impossible to tell from outside a new car (and sometimes from inside) whether it’s even powered by petrol or electricity. This slinky new Audi A6 is a terrific case in point. You’d pretty much assume from looking at its shape and its general demeanour, and its blanked-off grille, that it’s all-electric, and the subtle e-tron badges embossed into the door sills confirm this for the eagle-eyed.

Yet Audi seems insistent on muddying its own waters, by U-turning on its previous policy of giving electric cars even numbers and petrol, diesel and hybrid models odd numbers. You see, the A6 e-tron’s combustion and hybrid partner, just launched in Avant estate form this week, was supposed to have been the new A7. Yet at the last minute Audi backtracked on that plan, so now it too is the A6, despite looking subtly different (actually slightly more muscular) on the outside and being based on an entirely different chassis, shared with the Q5 and A5.

So the only real way you will be able to tell whether you or your neighbour is driving an electric Audi A6 is if it has the e-tron badge. The others will be badged as TFSI for petrol, TDI for diesel, and TFSIe for the upcoming long-range plug-in hybrids.

Confusing? Well, Audi Ireland’s boss Christian Gussen reckons that actually for most buyers it’s a far simpler thing – they will mostly come into Audi’s dealerships and buy the new model that most closely resembles the one they’re trading in, so the number on the badge is actually fairly irrelevant.

Equally, Gussen brushes off worries about Audi’s broader economic performance. With the brand, globally, worried by its sales volumes and profit margins, and with redundancies on the way, Audi could rightly be called a troubled brand at the moment, but as Gussen points out, last year it was the best-selling premium marque in Ireland, and its performance in Europe remains strong. The worries are mainly to do with the brand’s performance in China, “and in this I think we are in good company, unfortunately”, he says.

Perhaps worries about a more consistent badging line-up, then, are peripheral. Perhaps all the more so when you see the headline figures for this new A6 e-tron. Whereas before cars were judged on the size of their engines or their 0-60mph times, now the critical figure is range, and the A6 e-tron has that in abundance.

In fact, combine the biggest 100kWh battery with the 286hp single-motor rear wheel drive (yes, a rear-drive large Audi saloon, something that hasn’t really existed ever before) and then A6 claims 751km of range on one charge. Even allowing for some losses in real-world driving, that’s potentially enough to drive from Malin to Mizen and back up to Cork city.

Even the smaller 83kWh battery does well on range, allowing for up to 622km in the basic A6 e-tron model. Hitherto, Irish electric car buyers have generally opted for the larger of any two offered battery capacities in a given EV model line-up, rightly fearful of being caught out by our sclerotic public-charging network. However, the A6 e-tron seems to have so much range to burn that the orders taken thus far seem to be pretty evenly split between the two, and the smaller battery version may in time become the volume seller.

Then there’s the question of which body to buy. You won’t be surprised to hear us recommend the Avant estate. It’s slightly more practical than the fastback saloon version, certainly more handsome, and only a fraction worse off when it comes to range. True, it also costs an extra €1,800 above the €74,500 basic starting price (and you’d have to wonder why: surely the extra aluminium and glass can’t cost €1,800?) but on balance, and considering the long and expensive options list, it seems like a good idea.

You will instantly notice the low roofline of the A6 when, instead of climbing aboard as one does in an SUV, you instead slide down and left into the driver’ seat. The roof rails actually seem suddenly low and present, almost as if you’re wearing the roof as a hat, but while there’s not quite the open space you’d find in a similarly priced SUV, there’s room enough. Comfort enough, too, and quality more than enough – Audi has reclaimed its stake as the best builder of interiors in the game.

The big sweep of touchscreens (including a pointless optional one for the front seat passenger) work well and look sharp, but as ever can be confusing and distracting when actually driving. Thankfully, though, you’ll have other things to think about when you’re driving. Our Avant test car, in gleaming white, was a Performance model, so had a single rear-drive motor with 270kW, or 367hp, backed up by 565Nm of torque. Even so, despite the 5.4 second 0-100km/h time, performance feels amply brisk rather than outright fast.

However, the A6’s speed trump card is not in its acceleration, but in its recharging. Thanks to a high-powered 800-volt charging system, it can charge at up to 270kW (assuming you can find a public DC charging point with that much power) and can add as much as 310km of extra range in just 10 minutes’ charging – no wonder people aren’t so bothered about having the bigger battery.

To drive, though? Smooth – helped by the optional air suspension of our test car. Refinement is not quite absolute (there’s a touch of tyre swish and roar) but it’s close. The A6’s chunky weight (2,260kg) doesn’t merely blunt the acceleration, though, it also seems to put a slight dampener on driving enjoyment. The A6 corners smoothly and crisply, but on this test not with all that much in the way of fun for the driver. As a comfortable long-range cruiser though, it may well be without realistic peer.

The thing is that it won’t be the big seller. With the “other” new A6 arriving in the summer, this – really rather lovely – A6 e-tron will find itself playing second sales fiddle to the one with diesel and hybrid engines, which just seems insane. If you could have a car such as this, with performance and range such as this, and yet have to pay minimal motor or BIK tax, and potentially charge it up at night for chump change, why wouldn’t you?