We moved into our current house a few months back. In the last week or so our ensuite bathroom (near where our newborn sleeps!) has been smelling like a sewer. After some investigation, the issue is coming from the shower drain. I flowed through a few bottlers of unblocker in case we had a blockage - and no luck. Eventually I lifted up the drain grill and saw no water seal (i.e. no small pool of water) and so it looks like some element is missing and so presumably sewer gas is coming up unobstructed to the shower! As per the pictures it looks like something that sat in the internal bracket has been removed at some point. However, there is no brand name on anything - so I have no idea what to do! Any help hugely appreciated.