The motor is easy enough to strip out and clean.You can pull the plug to the motor and put 12v to it to see if its the motor at fault or the ECU/wiring. If you put 12v direct to the motor make sure you have a 5 amp fuse in line.combined with a little persation (sharp tap with a peice of wood) A...

sounds like your gearbox has gone into limp mode,Did you top the coolant up or run hot prior to the fault occuring? Some numpty at Land Rover decided to put 2 electrical connectors under the header tank,They get wet and corrode usually the first thing to show up is the gearbox banging into gear...