Academy decals are notorious for silvering. You have to really ensure a very glossy smooth surface combined with liberal use of decal softener to prevent it. Another trick is to wait for the decals to dry and then carefully prick the silvered spots with a needle, and then lay down another coat of solvent and use a brush to gently work the decal flush with the surface.

Here is a link to my Academy P-40E I finished about a month or so ago. I was able to keep silvering under control with the above methods.

A trick I learned to help smooth the surface even more is to use super fine steel wool (OOOO grade) to polish up the surface a bit. Mal Mayfield, aka Holdfast, recommended it in one of his features because it won't rub off fine surface details like sandpaper will.

Anyways, nice work on the diorama, and good job on the camo for the BF109. The only thing that looks incorrect to me is that the exhaust pipes on the nose got painted the camo scheme too. I would have chosen to give them a dirty metallic color instead, maybe with some rust color added as well. Even if they had been painted to match the plane's camoflage pattern, it would have eventually burned off from the high temperatures of the engine's exhaust.