We’ve got the Toyota C-HR hybrid – this is a ‘mild hybrid’ (I think that’s the term) – it starts on electric and will run for short distances on electric, the petrol engine recharges the battery – you can’t plug it in.
Watching the monitor it uses the battery to supplement the petrol engine when it can, and will occasionally run (even at high speeds) purely on battery. The overall petrol consumption is reported on the dash as around 65mpg on mixed driving (but very few long journeys); we’ve had as much as 99.9mpg on a 4 mile trip, and as low as 40mpg on a 30 mile trip. I have a strong suspicion that use of the air conditioning, and heated seats (not in this weather!) have a huge detrimental effect on petrol consumption – because these run off the main battery, and the petrol engine recharges it.