Ill need to look at my Centaur glass to see what the problem is... any chance you can tell me so i can do it the lazy way?

OK have a look at the below picture, I've added some arrows to show the problem.  To me it looks like the artist has tried to make the backglass look more black like the original.  But you can see the areas that have been added to look more black compared to the areas that haven't been touched.  There are 2 distinct shades of black on the CPR backglass, the original does not look like this.

You will need to open the picture so its bigger to see the fault.