stupots

Hi just travelled on holiday in my converted Alphard 2005 plate which has been converted to a camper, i have only had it about a week after waiting for 4 months for the conversion, my only problems are that as the car was a very low milage import from japan the display on the head display text is in japanese and some of the buttons . question how do you convert to english, i dont think there is a sat nav disk in it , the are two slots for disks when the head opens , a dvd size and a smaller size disk slot, is one of these for the the sat nav disk, or does it mean a new head for the english market. please help if you can stupots.