Eggy smell in living room

I suffered a similar problem and determined that the smell was coming from my ceiling light fitting. I changed the same and the smell has now gone.

The two most common reasons for an egg smell is a natural gas leak or sewer leak. If the smell of egg is strong then you may have a serious gas leak and need to call 911 and your gas supplier. Steve Slb plumbing

I would suggest it’s a problem with one of your waste traps but I would need to investigate further.

If it just been painted with B&Q pain valspar it will smell like rotten egg