Hi,
Interesting little project, seems like an ideal candidate for a silicone mould and casting resin.
First job would be to cut a piece of material (Plastic MDF metal... anything with a smooth surface) to the size and shape of the base plate, then glue your new lettering onto this to create a pattern.
You will then need to mount the patten into a water tight box that is a little bigger than the part, this box has to contain the silicone when it's poured waxed MDF or wood is fine for this as long as to joints are sealed.
You are now ready to make the mould, simply mix a batch of silicone that will fill the box, covering the pattern. carefully pour this over the pattern and leave to cure.
After curing the silicone can be removed from the box and pattern, this should remove really easily even though no release agent has been used.
Making the part from this would be a really quick process, just mix up a small batch of fast cast resin and pour it into the silicone mould (again no release agent required) this will be ready to release within an hour!
To finish the part up you would just need to sand the back of the plinth flat with a sanding block (as this was the open end of the mould and will have the od ripple), to fit it I would spray paint it to colour match, then simply grind down the original one and bond this in place.
Everything you would need to cast this part comes in a handy kit found
here There are no seriously harmful chemicals or smells involved so it's something you could probably get away with doing on the kitchen table!
Paul StathamEasy Composites / Carbon Mods - Technical