I can't stand it! We've just moved into a rental (Australia) it's a 1930s house and a lot of it is original. The loo in the main bathroom reeks...I thought it was the drain in there but I now see it's the toilet....it's a sewerage type smell...or strong pee....we have a septic tank and I've used bleach to soak it to try to kill the smell but it's still there. I realise now that you shouldn't use bleach when you have a septic tank but it's done now.
I've cleaned around the base...scrubbed it all but every morning the smell is back.
The seat is very old and worn...looks 1960s...but the smell seems to come from INSIDE the loo!
I know I can ask the Landlord but if it's something I can fix, I'd rather do it myself really.