Any purchase will be a private one with me adding 25k miles pa.
My sums were also done on the basis of 25k miles pa. and also assuming current MPG was not amazingly Eco, and having Economy 7 electricity to charge overnight and intention to charge a decent proportion of the time at work and/or Superchargers etc. and on that basis I calculated the saving between Diesel and Electricity to be £ 100 per month for each 10K miles per year. My commute to work is 40 miles each-way so I could easily do round trip and only charge at work, so maybe in I will save more. If your Jag is thirsty the figures might work better for you
There is perhaps?? [depending on how much Man Maths you can get away with!!] another £25-50 a month for congestion charge, car tax reduction, etc.
So ... doing 25K miles pa I took £ 250 per month off the HP payment to decide how affordable it was.
20K of my 25K miles is private, so £200 (of the the £250) per month is after-tax and mine is a company car, so the £250 extra on the finance will be a company-cost. There is also 100% first year [electric vehicle] write-off available (if you can buy in as a company vehicle). Of course for a private purchase the monthly fuel saving will only count 1:1, but its still fairly significant; in my case I have previously changed combustion-engine cars every 3 years (75K miles being my comfort-point before expecting to incur mechanical issues), whereas I think 150K or maybe even 200K is perfectly reasonable for electric motors, so finance of 5 years, and allowing for the £250 per month, might well get you 2x as much purchase-price compared to a combustion-engine car.
For a private vehicle, if you will be doing some business miles that will be recharged to the company, it would be interesting to consider if the standard X-pence-per-mile will apply - clearly that will be far more than the fuel-cost, so would also help offset higher initial purchase price.