I followed some instructions which I found on YouTube and updated my Satnav. However, I have 2 questions. Question 1: When you are updating the map in the car, which takes about 20 minutes, you are advised to keep the engine running. Can you do this by going for a short drive or does it need to be idling over on the driveway ? Question 2: When it comes to updating the next time, say 6 months down the line, can you just download the update & put it in the car or do you need to put the USB stick in the car first to register it again ?