Pop something thin (screwdriver with cloth around) into the space between the bottom of that section and the stereo.
It comes out without too much force, then the 3 buttons (C.locking, heated r.windscreen and hazard switch) have clips on the back which allow them to be removed, reconnected.
If you check the connections and make sure that when the hazard button is pressed, there is a definate click, it should be fine, but is common to need replacing (about £17 for the hazard button).