You can expect around 8 miles of range per hour with a regular wall socket / 3-pin this article lists some good options that you can set an adjustable charge speed up to 13A https://topcharger.co.uk/best-ev-chargers/ or you can get a Type 2 charger for up to 7.4kW which adds around 28 miles of range per hour. Remember to get an off-peak tariff so charging your car costs less than usual.
Best advice I can give you is to get off Reddit and ask a consumer lawyer to look into it. You need legal advice on something as big as a £20k car.