Hi, I have a Solidor that is just 3 yrs old, the company who fitted it has gone out of buisness and walked away from his commitments thus leaving me with a guarantee that is just now a worthless bit of paper. The door has developed some very small spidery cracks around the letterbox edge and I was wondering if a car polish with a colour enhancer would work. Any suggestions would be greatly appreciated. A pic has been attached.