Second-row seat space is generous, with enough room for taller adults even under a panoramic glass sunroof, although the seats themselves don’t slide and offer only outer-seat Isofix child seat points. Boot space is decent; just under 400 litres up to the window line, and losing out on just a couple of inches of loading height compared with regular GLCs, but countering with useful under-floor charging cable storage space.
Like other plug-in options, the GLE 300e leans predominantly on its hybrid system at town speeds, particularly so on a fully charged battery. It’s quiet and pleasant when running electrically, but it’s not as smooth or quite as responsive as rivals because its nine-speed gearbox is always fully involved in proceedings. It often needs to shift as you accelerate, and while some people won’t notice, you probably will if you’re used to the perfectly seamless and linear performance of an electric car.
The car’s outright performance when running electrically is adequate but doesn’t tend to make it feel particularly nippy or fleet of foot. Get deep into the accelerator pedal’s travel in order to seize a gap in traffic and you’ll likely rouse the petrol engine, and have a slightly delayed, two-stage response to your input to contend with.
However, the GLC 300e’s combustion engine does run smoothly and quietly most of the time and it provides what feels like an ample amount of grunt even when the drive battery has been emptied. Suffice it to say, though, it certainly doesn’t feel like 315bhp’s worth, let alone 500-odd foot pounds.
There’s just the merest background note of thrashiness about the 2.0-litre four-pot’s refinement when it’s working hard, but it’s never resonant or uncouth. When you do need the car to put on motorway speed quickly, for example, it pays to select a lower gear first in order to make sure the engine’s running and ready to respond. When it is, the car accelerates fairly keenly.
Running efficiency doesn’t seem to be this plug-in hybrid’s strong suit, though, and its electric range does little to recommend it, either. In a 12deg C ambient temperature, we saw an indicated electric range of just 17 miles. The car duly delivered that against the trip computer, but all of its rivals (tested recently in our PHEV SUV triple test) would likely have gone further. And most of those rivals would also return better long-range petrol economy, too: in a GLC 300e, it seems 32-35mpg at steady UK motorway pace is about all you should expect.