Supplied by dealer Northside Truck & Van, the 4x2 Actros 1840s are based at the operator's headquarters in Melton, East Yorkshire, which it opened in 2009.
The vehicles operate at 38 tonnes gcw and pull temperature-controlled 13.6m and short, urban trailers by Gray & Adams.
Heron's head of logistics Karl Dawson manages a 40-strong truck fleet, mostly tractors but still some 26-tonne rigids which are gradually being phased out.
He looked at the Actros late last year and realised the 2.3m ClassicSpace cab with flat roof was no wider or higher than the vehicles in the fleet.
"Not only do they offer the manoeuvrability we need, but we've also specified their cabs with extra side glass which makes for excellent all-round vision," says Dawson.
"We're very happy with their economy, too. Last month, our first two Euro 6 units averaged 9.67 mpg and 9.49 mpg respectively, and these are figures which compare very favourably with our non-Mercedes-Benz trucks."