I brought a Navigation update from the Land Rover website for my 2012 Range Rover Evoque. The update didn't work so Land Rover suggested I got a new USB stick from the Netherlands and let them install. They have had my car for 2 weeks and now say that the first USB has broken the main unit computer and I need £1500 for a main unit which they will pay 50 per cent of. If it was their product that broke the main head surely I'm not liable for the new computer main unit. Please advise me on what to do.