Warranty comes down to the garage that inspects it and the conclusion they have come to. In my experience it is very little to do with the warranty company as the inspector will just come and see the car and take some pictures. A HV battery can be a wear and tear item, but if it is a result of another fault like fuel pump for example, then more often than not they would warranty the lot. It's hit and miss but if you have a good garage that are on your side, its more often warrantied.