To produce a one off custom light cover, you'll need to send me a tail piece and light, then I Sculpt onto that which doesn't damage the light or tailpiece, once this is done I make a mould of the work to produce the finished piece in fibreglass, then attach the fibreglass cover over the light and filler and bolt that to the tailpiece to produce a sealed seemless finish.
You can contact me on Chris@custom-sculpt.com or call me on 07976 818108 to discuss
Here are some examples of light covers I've produced . .
St George & The Dragon