Try these folks.....

VIN PLATE TAG | Aftermarket VIN Plate Suppliers

At VIN Plate Tag we specialise in producing blank reproduction VIN plates, chassis plates, data plates and

vinplatetag.co.uk

 

Try Jerry Turner at Nostalgic Reflections. It’s a dot com with the name as one word. Not cheap, but he will restore yours, or recreate one exactly like it with the letters and numbers raised above the surface as is your original. I kept my original it was done so well and kept the reproduction as a spare.
Or, you can just buy a $10 copy printed flat on an aluminum plate, a search on other forums will produce a lot of threads on those.