Bumper Part needed? Whats it called??

I noticed yesterday that a stone has broken part of the fog surround on the way back from picking my car up on Sunday. I can't find the part on eBay at all and need some help if possible? It's not the fog surround but the smooth bit behind that feeds air to the brakes by the look of it. Is this part of the bumper or a part that can be bought separately?

Thanks
Joe