The glow driver and glow charger are probably fine. With a load on them they will read 1.2 (more or less). I'd take a chance and try a glow plug. I'm 99% sure that it will be OK. I do not have your exact power panel. Some panels just use a big resistor in series with the 12 Volts supply to drop the voltage. Some pulse the 12 volts. And the charger may be just a constant current charger, so again the voltage is meaningless measured without load.