EVCostChecker Will let you enter the cost of running an ICE vehicle against the cost of an EV. If you can charge at home, it is vital to see if you can have a smart meter and smart tariff for off-peak low-cost charging. Many members use Octopus GO, but shop around to find the one that suits you.
Don't forget to see if SalaryBoost from Wyre can help you in the transition by offering preferential leasing terms.
Want to buy secondhand, check out EcoCars, who will source cars at auction to your specification.