Out of interest, what is your current car? 28 mpg is shocking. Our last petrol car averaged 42 mpg and that was a petrol 4WD SUV! Is it a Volvo? Their petrol engines seem to drink like fish!
The question is not whether you will save a lot of money as that’s a no brainer (you will) but if a BEV would suit your needs, and only you can really answer that!