After no more than 30 minutes in total, the psychedelic plaything suddenly slips into limp-home mode. The range indicator is down to one kilometre, first gear only reluctantly picks up speed, the battery harbours around 10% of capacity, and the display suggests we contact the nearest dealer. What would you do with a complex electronic device at home? Turn it off, then on again, of course. Then select Sport, and two laps at seven-tenths restores the battery. The petrol engine drives the high-voltage generator to replenish the charge, and it’s as hush-quiet as it is free of any coupling or decoupling irritations. But it’s not as efficient as hooking up to a charge point though, cutting economy to around 37mpg.