On and Off button

Thanks for the picture. It helped, but not by much. This unit i haven't even seen in North America and judging by the fact that steering wheel is on the wrong side of the car i may never see it. However in answer to your question. Top of the unit folds down and slides back into a slot. Should be able to gently pull it forward and then slide it back into the slot that is behind the display screen.
2- If you are not afraid to play with the buttons press them and see what they do. This unit looks like it has a touchscreen so you should be able to exit the gps side of this and go into your music files and other files on the unit. You should be able to find the features and setup screens that you want under the setup menu.
3- These devices are designed so that when key goes on, they go on so if the unit will not shut down when the key is turned off -- it is most likely hooked up to the wrong circuit. Only circuit that should be hooked directly to power is the clock circuit. I could tell you some of the wiring but not sure the European cars are hooked up the same way and follow the same wiring as N American Cars.
4- Sorry it took so long to get back to you but i am a long haul driver and was out of town on a run. Think you call them Lorry drivers over there. If you need more help or think i may help you more feel free to contact me. I do hope this helps you ouyt though.