Replacing broken ring

I fitted a Ring Pro in January. Since then the glass (Perspex?) has cracked and peeled away and looks terrible. The retailer is sending me a replacement tomorrow but I have some concerns. If I whip the old one off and stick the new one on, will configuring it to replace the old one be simple and straight forward? Does any one know why the glass cracked and peeled? It gets the sun all day, could the sunlight have done it? And lastly, can anyone suggest what I can do to protect the new one from suffering the same fate? I’m thinking of taping over the glass leaving a gap for the camera. Will look rubbish but so Does cracked glass. Thanks