Just charged mine fully from 68% last night. Took 7hrs 40 mins and left me with 324miles. Fairly happy with that as it’s got nearly a years info to work on. My mileage is low too which may have a bearing too. I’m confident I could get that without trying hard too. Certainly better than most cars that seem to just kid on what you may get.
We had a 1 series BMW 120d M Sport, official combined mileage 62.8, actual around 40. So, the Kona beating the official WLTP is very good. I am not too surprised as our Tucson, although thirsty, achieved more or less, its official MPG, whilst our X1, and Octavia struggled in this regard. Likewise, Hyundai’s always beat the official 0-62 times.