Why would you need two 12v batteries if it was a 12v vehicle? I think this person may have a 24v FFR, so batteries between seats, someone has changed the ignition system to a normal unscreened distributor and coil, but retained 24v for started, generator, etc. Running the ignition from one 12v battery. If so, bodge seems the operative word.
If it were a 12v Land Rover it would have one battery beside the engine, so where would the second battery be?