Some of our rules regarding vehicle requirements apply to the date of manufacture, others to the date of first registration in this country. Because this car was imported and first registered here at a later date, that means it legally requires a high stop light and won't pass an inspection without one.
The standard style window mounted lights are huge and really obstruct vision out the back. The one that came with the car departed quickly, replaced by a 'slim' LED one, but still quite large on the window and annoyed me. I finally got around to plan B, made a small housing flush mounted in the spoiler with a bright red LED strip inside it (its completely white/clear when not going).
Also made a spring-loaded contact for the power supply at the left hand rear corner, uses the same spot as the compartment light switch on the right side but instead of earthing it has an insulated power wire pass through it to a contact on the lid. No more wires hanging out.