Hiya Gareth thankyou so much for the advice and I apologize for the slow reply. I will be getting some bulbs tomorrow to test this but just out of curiosity like I said the bulbs still work perfectly fine and have done for over a year and now like I say it's throwing up that message while they still work. Does that mean the resistance would change over time? Could it be due to cold weather or anything like that? Regards.
Ashley