Rosemary

Hi, I have reversed into a wall in the dark and a part of the black fascia(?) strip along the back, that contains the sensors (which are not affected) has fallen off. It's a square about 7cmx7cm and seems to slot into the grill. I'm calling it a grill but it's solid and more decoration than anything else. What should I ask for in order to replace it? Many thanks for any help Q3 quattro 2015, 80k miles, diesel S-Line