Did you ever get to the bottom of this Shrew? I've just had fault P0685 come up a number of times and the engine cuts out each time. The dashboard instruments stop working, the clock stops, the interior lights won't work, nor the central locking, the radio goes dead, some of the warning lights on the central check panel don't show, the windows and the hazard lights won't work. But the engine will crank on the starter motor and the speedometer needle sweeps round the way it does when you have a dead battery. Any ideas please?