I've had my RRS PHEV for about 9 months and, soon after a recent software update, I got a notification from the security monitoring service that a potential theft had been detected due to a loss of power. When they checked it, they said it looked like a dead battery had caused it, and that's what it turned out to be. But this is a spontaneous complete loss of charge, over the space of just a few hours, and nothing was (or could have been) left on. I had to get roadside assistance to give me enough charge to drive it to the dealer. They had it for nearly a week and gave it back to me supposedly fixed. They simply applied a bunch more software updates and checked the battery, which they said was OK. Now, less than a week later, the same thing has happened again.

Is this a battery problem or is there something in the car that is draining the battery?