Basic maths,
ICE car @ 36mpg and £6.45/Gallon (£1.43/Litre) = 18p per mile
Full EV car @ 3 miles/kWh
Home charging at 7.5p/kWh = 2.5p per mile
Average public charger at 69p/kWh = 23p per mile
You maybe better off with a full hybrid (FHEV) these do a much higher MPG than a standard ICE car so could reduce your petrol consumption by up to 50%.
Looking at the Kona Ultimate,
ICE AP £2199 + 8000 miles at 36mpg = £1,433 petrol x3 plus AP = £6,499 over 3 years
EV AP £999 + 8000 miles (public charger) = £1,840 x3 plus AP = £6,519
EV AP £999 + 8000 miles Home charging = £200 x3 plus Ap = £1,599
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!