LIKE the generations that preceded it, Audi’s new A6 Avant is a bona fide alternative to the established medium-large European load-luggers from BMW and Mercedes-Benz. With two competitive V6 petrol engines, an array of cutting-edge equipment, the latest safety features, impressive refinement and build quality that’s now arguably the benchmark in its class, the latest A6 Avant makes a persuasive argument for families that are prepared to pay for a top-class German estate car.