Plumbing issues, smells.

[SquinkiesRule]

It making me a bit crackers here, the stink is vomit inducing.
We just moved back to UK, we are in my mothers house, she is away at the moment. Heres the situation.
Dorma bungalow, family bathroom is downstairs, upstairs is an ensuite shower room.
House attached to us is the end of the line so to speak, the sewers run from them to us, to the next door thats not attached, an on down the hill. (this is according to my mother who had to have the drains fixed a few years back due to a block two houses down).
Downstairs bathroom gets an occasional smell that is foul, smells like a sewer, I can't get it to happen on purpose so it's not after we use the shower or loo.
The smell comes up though the bath and basin drains only in the downstairs bathroom, upstairs has no smell at all.
Really trying not to drip feed here, but we haven't lived in UK for many many years, not sure I want to have to live with this.
Any ideas?

normally there would be a level of water in a U type bend in any drains that would prevent aromas coming back up the pipe - sounds like this isn't being sustained - therefore they may be a leak - unless the smell is coming from outside ?! is the soil stack in good order ?!

just re read your post - the bath and basin should both have their own U bend underneath the drain - if the plumbing doesn't appear to have this - that will be your problem - easier to check the basin - just look underneath - you should see a u shaper or more often a bottle shape trap underneath - baths usually have a shallower U shape . if these are missing a plumber should be able to fix this by installing a P trap and bath trap .reasonably easy in most circumstances .

What is the soil stack?
I'm a complete newbie at this, we've been abroad 20 years, and only visited.

The bathroom was re done 20 years back and this problem has been happening for the last two so I'm now told.
There is a large U bend under the sink (just looked)
How can a smell come from outside? Would it be coming up the overflow in the bath ad sink? Or is there any pipe not protected from odors by a U bend?

well it sounds like it's been installed properly - which means the smell is coming from debris in the pipe work I expect - if you go to your local DIY store and buy a flexible pipe cleaner ( looks like a tightly coiled springy thing) and carefully put it down your drain hole in your sink and in your bath - after a good wiggle around you may find a clump of yuck will come out with it !(ewww) when you pull it back out ... boiling water might help too and strong bleach - thick domestos or similar night solve it !

an older house will usually have the soil pipe rising up to roof level, where it will be open to the air.

If you have had a rerofitted bathroom it might have a Durgo or similar plastic air admittance valve inside the house instead. these stick. The sort of person who like these awful valves usually likes to conceal them behind boxing-in and tile over to make it as difficult as he can for you to examine and replace them.

Otherwise you probably have a partial blockage. Open up any manhole covers. Are they empty? Do they smell? Does water flow easily and quickly through them? Have you got any yard gullies, and do they flow freely? Does anybody pour cooking fat down the sink?

You are all a wealth of information. I will ask a friends Dh to open up the manhole cover at the top of the driveway to see if everything is flowing. Once it's light and I do the school run I'll look outside and see if I can see the soil pipe (I think they called it a vent pipe where we lived before) Next shopping trip will include some thick bleach. I did boiling water this evening, and it did a quick stink an hour later. If it were constant it would seem more like a block to me, but it's the random sudden stink which then goes away that I find confusing. Leaving the plugs in the holes seems to cut down on the strength of the stink, so will do that till resolved. Last resort is ask the local plumber. Dh arrives next week, I can get him to snake the drains if I have had it resolved by then, he's my Mr fix it, but isn't used to UK set up so there will be a new learning curve for him.
This summer he had to fix a massive block in our pipes and due to lack of space moving to UK, he gave all the drain snakes to a friend.

from your description, it is a drain shared between several houses (a common sewer) and the shared part of it (but not your house) is the responsibility of you local water co, so get them to have a look. The sewermen are usually very experienced so if not their responsibility, are likely to have good advice.

Last time I had one, I gave him a mug of tea and a doughnut, and he sat on the edge of the manhole, with his legs inside, eating the doughnut with his rubber gauntlets on.

eeeewwwww !!!

it may be poo to you, but it's his bread and butter.

LOL at the man in the hole with his tea and doughnut.
We have a normal soil pipe, it looks huge to me. I did notice it has no little basket looking thing on top. I wonder if a bird tried to build a nest on it, and has dropped stuff inside, I know a birds nest followed by a bird came down the chimney about 18 months back. I'll ask friends Dh (who did the bathroom 20 years ago) to have a look.

Thought I'd update with the fix.
Called my friends Dh in, he installs bathrooms so thought he might know, he said it was the bend in the pipes it gets gunk and hair in there. Told me to get thick bleach and let it sit in there overnight.
That made it a bit better I did it two nights in a row.
Then my Dh got here and fixed it, it pulled off the bends and cleaned out the pipes and sat bleach in again, and all is well, house smells lovely again.

see if the waste pipe can be rerouted so that it runs smoothly and evenly downhill, with minimum bends and elbow and no dips

Water does not run uphill so you will always get sludge, stinks and blockages otherwise.

Plastic piping is quite easy.

or, if you meant the trap, a "S" or "U" shape is far less prone to blockage than the "modern" bottle trap, because the water flow tends to wash them clean. If you have bottle traps, buy some washing soda and a sink plunger, and learn to unscrew them yourself. They will be revolting.

I call it a U bend, thats the shape of them, Dh unscrewed them and cleaned it all, funnily enough he had to do our house that we just sold as we were starting to get an occasional smell.
We are going to be ripping out that bathroom and starting over, putting in new everything so hopefully we will have no problem again. Might not be till next year though.

washing soda and a sink plunger are very effective and cheap.

I think there must be something stuck in your pipeline which has now started to stink. Can be anything,you ca be grateful that there isn't a clogged drain. Sometimes the block causes a random stink. I cannot think of anything else. The best thing to do will be to call the property plumbing people. They will know what the problem is and will solve within a day. You will not have to suffer that stench longer. Since you are new, ask any of your neighbors for their number and give them a call.