my cmax i used to own was pretty terible unless sitting at 50/65, when it got about 45/50mpg. but in town and pottering about it could be 16/25mpg. cost a lot in fuel, but was a great car otherwise.
no issues now as i dont use petrol/diesel anymore.
Current Car: Hyundai Kona Premium EV...2 way 40kg hoist
Last Car: Toyota C-HR Excel Hybrid...4 way 80kg hoist