you call it oxforders
People who attend the University of Oxford are normally posh as they commonly have a history of rich family. People who live in Oxford are anything but posh
The word for an "Oxford bigwig" would likely be don.
Oxonian
Oxford
Californians
Maltese
I suggest you call Oxford Insurance customer service and ask them for a list.
People who live in Germany are called Germans
People who live into their 80s are commonly referred to as octogenarians.
The people who live in the Philippines are called Filipinos.
Oxford street
I imagine lots of people do it around the UK that live near towns, for instance I live near enough birmingham for people to call it town, and my cousins who live near Manchester and call that town too.