See? At least on my car the spare wheel would hide the light:
Ivo: we were shown around the car by Matt Humphries (on the photo in the grey suit) and the hood is altered at the back to accommodate the brake light and as you can see from the photo it is in a slightly higher position than yours. Also, it looks as though the spare wheel on your car is a full-sized spare, whereas the spare wheel on the Roadster Sports is a space-saver wire wheel so it does not stand as proud; thus giving a proper sight line to the 3rd brake light.
