I can start my rover up and drive it for 10 to 15 minutes and as I'm driving the rover shuts off as if someone turned the key off. When it comes to a stop I can turn the engine over but it won't start, but if I leave it for about an hour and try to start it, ti will start up, then it does the same thing.

Gary Adams, January 2011

Had a similar problem on my V8 Disco. I could be a dry joint in the immobiliser supplying the power to the coil.
When it stalls again, get a multimeter and check the power supply to the coil, it should read 12 volts. If it doesn't then run a temporary power wire from the battery straight across to the coil. Your rangie should now work again. For a permanent repair, run a new wire from the ignition to the coil (bypassing the immobiliser).

Vince, January 2011