Hmm - there must be an issue with the alpha settings - this was probably set up before transparency was introduced. I cannot rembmer the exact location of this in the menus now as I am away from home and without access to the computer that runs Blender, but there should be somewhere in the material settings for the grill material a setting for alpha transparency - you just need to reduce this to make the material more opaque. I hope that this helps. Thank you very much for your work on the liveries - it is a splendid thing to have people working on this.
