FTJR,
I think Mus does a good job of pointing out the weathering details when he edited your picture. I would try implementing something similar to what he is suggesting.
Now Krusty also brings up a good point too. Silver painted aircraft generally have a bland appearance with little weathering visible, especially on those that are freshly painted. Also, you may want to play with your specularity settings. I notice a few things between BMF and Silver paint with the following:
1. BMF has a very bright reflection when shown in light. However, the size of the reflection (area that is reflecting the light source) is small, and as such, gives it a mirror-like luster, and you can see the sun, light bulbs, or other sources of light as if you were looking into a mirror.
2. Silver paint has a different kind of "luster" or specularity assiciated with it. Reflections are not nearly as bright as BMF. Rather, the appearance will seem dull in comparison. But the size of the reflection (amount of surface reflecting light), is much larger, as the paint spreads light across the surface further than bare metal.
If you look at Krusty's images of the B25 that he posted further up in this thread, you will see what I mean. I think that you might be able to depict the specularity as mentioned above, and perhaps the silver painted Mossie wont look too cartoonish.
So essentially, you have two choices. You can either depict your skin as being a freshly painted Mossie on the first day it saw action. Or you can depict the Mossie after having flown several missions and collecting dirt, oil, and other weathering. Either way, there really is no right or wrong. Just use your imagination!