Why do my plug holes keep gurgling???

[SmiledWithTheRisingSun]

In my bathroom. Both the sink, bath & toilet?!?!

They sound like they're going to erupt! It's very disconcerting.

Is there a foul smell too?

Sounds like a blockage or partial blockage in the waste pipe after they join.

Yes it smells horrible.
Do I need to call a plumber?

Plumber or someone, you can get snake things from Screwfix to twist down the drain, but you need to have a bit of practical skill. Even a handyperson could have a go

Try shoving some soda crystals down and a couple of kettles of not-quite boiling water. And or the old bicarb/vinegar trick. May clear the blockage.

yeah get some drain cleaner for each one - make sure its the same. It all generally goes down the same pipe at some point to join with the waste pipe outside. My shower travels a long way with not much of a slope as does the sink although with more of a height drop but if you empty the bath sink and shower drains can hear the water and I think a bit from the bath flows the wrong way IFYKWIM