Every motability car I have had I have fitted better tyres, whether they be all weather or winter tyres. On an Ev you might lose a little mileage but you gain an awful lot of security over summer tyres in winter. With the right tyres you can go most places a 4×4 on summer tyres can go in winter or on mud. Some of the all weather tyres are fantastic, you can find the test results online. Germany has been doing testing for years and you can cut and paste into google translate to see for yourself which brands are best.