I made 14 of these external light fittings to suit our wall cladding. I used a timber back, Mini Orb, otherwise known as Mini Corrugated, and aluminium sheet reflectors from Bunnings. They all fit bayonet cap fluorescent lamps.
Looks good at night and the lighting works as well.
There is a grommet at each exit through the Mini Orb cladding. Being a retired architect, I am somewhat trepidatious about safety having seen what a sliding door can do to a flex not grommeted in a steel stud framed house.
The light fitting is really just some cladding on a hardwood backing plate with sawn holes for the batten fitting, which is a standard batten holder for bayonet lamps. I then screwed the fitting to the building cladding with a layer of insulating rubber behind the hardwood at each screw fixing. All fittings are in protected positions under verandah roofing or extended eaves, offering protection from down flow and wind-driven rain.