The Kia Soul EV, Kia e-Niro or Hyundai Kona Electric all sound like good options. They all have generous ranges, represent good value for money and should be able to handle your bumpy lane fairly well. You could also consider the MG ZS EV - it's an electric car bargain, but its official 163-mile range means you'll probably have to stop to charge on longer journeys. Unfortunately, due to demand, electric cars aren't usually available on scrappage schemes. I'd recommend selling your BMW privately to get the most for it.