Plumbing problem: sulphur smell mystery

[WeLoveYouMissHanigan]

Can anybody help? We have a sulphurous smell that happens intermittently after showers

it’s worse after heavy rain or dry weather.

We have so far had two plumbers out (apparently all the plumbing was done correctly when we had bathrooms replaced last year).

Also apparently kitchen dishwasher was installed fine - also verified by two separate plumbers

today we had drains checked over and a fatberg removed, cameras down and drains disinfected

Thought that was the end of it but tonight my son and I both had showers and the smell came back. Smells like it’s from inside the house now.

any ideas?
what do we do now!

Do you have an external stink pipe or a durko valve? Foul waste can vent through a shower
Durko valves can become a bit stuck and not vent properly

*durgo not durko

Hi, do you mean the soul pipe chimney? Yes we have one

Yes
I had a house where the foul waste vented through the shower rather than the stink pipe and it was as you say - intermittent and pungent like sulphurous eggs

We had this and it was because the trap in a very rarely used loft-conversion bathroom had dried out allowing smells to come up. Weirdly caused a rotten egg smell on the landing below when the showers in the other bathrooms were used. Worth making sure it's nothing like that. For us it was solved by running some water upstairs now and again to refill the trap.

Have you got a Watertown, in the loft, grim as it is you need to check nothings got in and died,

water tank ffs

Probably the durgo valve. I read a lot about them when doing our extension.

I think we may have solved the problem although if not, we will definitely investigate the durgo

some fatberg was in our outside gully. To big to have been brought up (wouldn’t have for through the grid). Can only have come from the waste pipe: Our waste pipe runs outside so we were able to throw a bottle of bleach and bucket of water and drain unblocker down. We also need a lid for the pipe as I can’t believe it was open to the elements.

Smell of rotten eggs/Sulphur in bath area.

Have tried drain unblocker and Bicarb.
Loo ok Sink ok, no smell
Stack vent pipe is too close to external window, but the smell dissipates when the said window is open. I do not beileve this is the source of the smell it is definitely the bath plug hole and overflow area.
had it before but it is temporary, had it now for 2 months
All plugs and loos draining well.
I never put fat down sink.
Lived here 20 years,

HELP!