Ok so I need a reasonable size car firstly. The Juke, Leaf, Golf, DS3, E2008, Prius - none of those are big enough.
Secondly I'm not sure you are quite understanding my point.
I currently spend £400 a month running and maintaining my old car. That is dead money, I have nothing to show for it after 3 more years.
I could get a new car on the salary sac scheme at work that will cost me £450 a month (the MG5). Yes I also have nothing to show for that over three years either. But instead of driving round in a 19 year old petrol BMW and carrying all that repair risk and worry, I will have been driving round in a brand new all inclusive MG5.
If I'm buying a second hand car I will need a loan. If I don't buy an EV, that loan is on top of the fuel costs, so I can't offset the cost of the car with the fuel saving. Hence, even though it's a newer car and I carry less risk the outlay per month is still higher. I am also still carrying risk, I could buy a £17k car tomorrow and in 6 months the engine fails. That liability is on me no matter which car I buy.
If I buy an EV with a loan, it's a hefty loan, needing around £20k. So whilst I do then own the car (and still carry any out of warranty repair risk), I will still increase my monthly outgoings substantially even with the fuel savings.
Consider my position from where it is right now - a £400 per month cost of running a car which is 19 years old. How can I a) reduce this or b) keep it the same whilst getting a better car?