[zetec]

That depends on the car, the Mk I cuts power to the ciggie lighters when you remove the key, but the new one might be different.

I believe the velcro straps in the boot are just perfect for either a fire extinguisher, safety kit (triangles etc) or even a first aid kit. It's up to you, but I have an extinguisher in my boot and I'd definitely put it there if I had the strips.