Closest one to Oxford I know of is in Woodstock, and in game. Lots of Victorian roads/houses, and the Victorians always blamed when sink holes appear, in Broad Street for example, terrible that the Victorian brick sewers have only lasted 120 years… but I wonder if the proximity of the big open sewer called the Thames meant that they didn’t need them!
The originals have cast iron bases, usually fluted or engraved. The original pipes are also cast iron, often decorated and topped off with finials.
I could give Niantic a clear guide to stinkpipes if they want to be selective in which ones are allowed. There are some very bad examples, but it’s insane just to delete them all like is happening right now.
Poo sticks… Official name is Sewage Vent Pipe which is not so fun as stinkpipes or poo sticks (the big one near me is known as the sh11t stick).
They are pretty cool. Not only do they expel the smell - by doing so they also stop those gases forming acidity that rots the pipes!! And where those gases are explosives stop things from blowing up. That big one I mentioned early used to burn off the collected gases as well. Which was fun as new people to the area call the fire brigade.
Good luck finding out what is going on!