Audis have always struck me as a halfway house between BMW and Mercedes-Benz, offering a flavour of BMW’s driving performance prowess with a smidge of Merc’s interior quality.

I made this comment on my first review of our long-term A6 Avant review to which one reader responded that, in their opinion, Audi had overtaken Mercedes for quality some years ago.

He perhaps has a point – certainly the gap has closed substantially since the last generation A6.

The cabin of our long-term test model, which first went on sale three years ago, is all tactile soft-touch plastics and leather trim, push button controls and ergonomic layout.

Short-cut buttons make navigating each element of the multi-media system, from telephone to music, car set-up to sat-nav, a breeze. You can even use voice instructions or Audi’s notepad which enables the more dextrous of drivers to write destinations.

It is supposed to speed up the process but, when you are not left-handed, it becomes a challenge to form adequately shaped ‘e’s and the like.

Audi took us slightly by surprised when the Avant arrived, rather than the saloon we thought we’d ordered. But it’s turned out to be an excellent choice thanks to a cavernous 565-litre boot which has made family outings a relaxed affair.

It’s eradicated the protracted arguments about which ‘vital’ items will not be making the journey with us; pretty much everything fits.

True, the A6 is not as spacious as the enormous Mercedes-Benz E-class boot (an astonishing 695 litres), but it is slightly larger than the BMW 5 Series’ 560-litre luggage area.

We’re making solid progress on the efficiency front. The commuting average continues to hover around the 45mpg mark, but longer trips have crept up to 55mpg, a whisker away from the official 61.4mpg combined figure.

Just one quibble has come to light since the last review. The windscreen washer needed refilling but the purchase of a four-litre container revealed a design flaw: the refill cap is sits snugly beneath the bonnet hinge so the bottle doesn’t fit under.

The solution? Transfer the washer fluid into a smaller vessel before pouring.