Isn't there a danger that the "earth", brown terminal might actually be connected to earth, so if you connected the red wire to it, it would go bang?
It will indeed blow a fuse if it’s connected backwards, but I don’t think the earth terminal on the light is connected to the engine lid. Can’t remember.
Pretty sure it isn`t , so fit `em to whichever you like but i`d check for earth using the beeper setting on mi far-too-fancy-for-the-likes-of-me multimeter and use the brown to earth
Probably isn't but you never know what the fixing screws go through. I'd stick to the conventional wiring of brown wire and side of bulb is earth and bottom of bulb is +ve.
The screws secure the whole unit onto the tailgate through the plastic of the lens as per your pic - should be fine ...
There is a full wiring diagram on ratwell which includes wire colours and + / - etc. I on my phone so can’t find it right now but a google on a tablet / pc should find it.