Ian,
Welcome to the forum! :) You might want to try giving the following technique a try before you strip off the topcoats and decals. If this works then you might be able to save yourself the time and effort of stripping and refinishing.
Take a brand new Xacto blade and cut tiny slices in the decal. Try to cut them discretely like along color demarkations (sp?) or other places where you can sort of blend in the cuts. After making the gentle scores with the blade, brush some Future floor wax over the decal. This may reduce or eliminate the silvering problem entirely. Once done then you can just go back and touch up the decal with some flatcoat. I've heard this might do the trick. I haven't tried it myself but long ago when I was a kid I had a bit of success using the same method using MicroSol instead of Future. I think you'll have much better success using Future.
Best wishes!
Eric