I haven't been in there for a while, but.......
The two rivet heads visible are blind rivets and will prise out with a screwdriver, leaving two holes. They are decorative only.
The lenses for fog warning and reversing are silicon sealed onto a large pressed metal base which screws direct into the rubber mount. Last time I looked I could get at the bulb, because I remember the connection was poor.
So have another look. If necessary you can take the whole thing off by accessing the rear through the spare wheel well.
They don't refit well and need some silicon lubricant to screw the whole way in.
Note this is where these lamps have rubber mounts, similar to the front indicators, not the current faired in lamps.
