to ask you how to get rid of the stink?

[myoriginal3]

Stink of sewage coming up through shower plug hole. It's definitely coming from there. I have tried toilet cleaner down hole but smell subsides for minutes only.
I have also ran shower for several minutes at a time.

History:
Overflow of toilet cistern rectified third January.

Only today confirmed that shower was source of smell. Smell is new but I attributed it to my own ass until repeated bleaching of toilet and opening shower door and nearly collapsing from the honk.

What can I do until rectified?

Our shower and sink dry out and smell, I have used vinegar and bicarb, it fizzes rather interestingly, but it didn't resolve the pong.

Zoflora makes me feel ill, more so than the drain smell. I keep a supply of Spirits of Salts in the garage and use it every 6 - 8 weeks. It removes smells, gunk, soap scum, limescale and also the finish of the chrome around the plughole so needs to be poured in very carefully.

I put some in every sink, toilet, shower and bath, leave it for a while (don't inhale it) and after about 20 minutes run cold water, flush or rinse. Smell goes. 'Stuff' can still cling to the pipes even after a clean/bleach. Remove it and the smell goes.

I use about half a bottle in each drain hole.

Get some of those disposable gloves, half fill one with water, seal it and that will make a temporary plug.
Its the only way to block the smell.

To be honest a toulet cistern has two methods of dealing with an overflow either a overspill pipe usually 21.5mm plastic takes that water to the flush pipe/waste/directly outside or any overspill flows through the flush valve and directly intoto the pan. If you have only ever had the cold feed and possibly a flush pipe if the pan isnt close coupled then it is unlikely plumbit would have even touched any waste pipes. Smell issues can be caused by a blockage further down the main sewer, shower traps tend to be shallower and the easiest exit point for nasty smells.

If you look at the plug hole, you'll have the outer (assuming silver) edge of the plug hole/waste. Within that you might have a cross shape pattern which catches hair etc. But within the circle you should be able to see another circle.
Find a something you can hook under this inner circle to lift it up. I use a small blade out of a pen knife. Once this is off you can see a, usually, white piece of plastic below. Hold this white plastic bit and twist and it should lift out, it's a hair catcher. If this is the cause of the smell it'll really stink. Clean the plastic part and then clean down the actual plughole too. Once all clean reassemble and run some hot water and shampoo down the drain.

No idea of course this is the problem with your shower but it is a common problem that makes showers smell or not run well. Attached pictures are example plug and the plastic hair catcher

OP "Smell is new but I attributed it to my own ass"

Um, is there a typo in there?! misses point

I had this in a rental.. someone came along and poured a load of carbolic acid down the drain

Nope. No typos. I neurotically cleaned bathroom for days before finally concluding that it wasn't me polluting the place.

My shit don't stink.

Sounds like it could be trapped hair. That stuff really stinks if it's never dealt with. pterobore has given some great advice on how to deal with it. If you can't get to the trap, Spirits of Salts will help.

if it's a sewage smell and it's coming up the plughole, I suspect a plumbing fault. This is more likely if the shower was added to existing plumbing after the house was built, or it can occur if there is a blockage in the soil pipe.

A Durgo can smell if it sticks open, but that won't come up the shower plughole.

You can give the shower waste a good clean. Some of them have a "mushroom" that you can lift off to clean out a trap. I prefer washing soda crystals, which will remove typical grease and soap sludge, and will not burn holes in your skin, clothes and eyeballs.

The water trap in the shower waste should prevent smells coming up from the drains; if it doesn't then you have an incorrect pipe run or a blockage. Experimentally, put a wet cloth over the plughole, see if it bubbles up when you flush the WC (it shouldn't). If you leave it there, see if it blocks the smell.

How old is your house? Does the soil pipe run up the outside wall, or in a boxed-in duct in the corner of the bathroom? Can you see the open end of the soilpipe at about roof level?

It's a council flat built in 70's I'd reckon.
Don't know where waste pipe is.
Will try your suggestion in a mo

Oh... we have this too in our downstairs loo. My husband swears he can't smell anything but I think it smells rank!

Forgot to update. Nothing coming up when flushing plus no smell today.

I too have a Dp lacking in the olfactory department.