Light fixing for a caravan

This is a box for mounting backup camera, backup light and number plate light on a caravan.

The original box for the numberplate lights was to small to mount backup light in, so I made this box. Its made in three sections and some support pegs to help join the parts together.

I had some problem with delamination on some of the walls, so I made support plates/walls to glue inside.

Its made with ABS, glued together, Then I tried to smooth the joints with manually melting filament. It tuned out OK, but not great. I then sanded it, used fille rprimer, sanding, filler primer and so on several times before I painted it.