Alternation to the vehicles lighting for instance like uprated bulb could result in damage and overloading to the vehicles wiring loom, if you carryout such modifications you could find yourself liable for any damage.
You also have to consider replacing the light bulb with non standard items could alter the lighting scatter pattern, if it dazzled another driver and it resulted in an accident I leave than concussion to yourself.
You have to remember after all it is Motability’s property
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.