With the MRA running rampant in the US, the Institute relocates to the much more friendly UK. While the plan was originally to expand the university outside Maldon to accommodate the Institute, the UK government made that difficult, instead requesting that the new mutant haven be moved to a new campus location outside of Cardiff, leaving the Institute and University as separate, but related, entities.
With mutant assistance, the Cardiff location was quickly constructed and when the time came to look for staff, the members of the first class from XU became the primary candidates. This provides the Institute with both the ample protection of seasoned heroes and mutants comfortable with a variety of powers to tutor the next generation.
Assisted by the Intercept operating system, a large portion of the campus is fully automated. The campus has its own Danger Room, though this isn't public knowledge and it is supposed to only be used for powers practice. There has been discussions of fielding the Institute students in non-hazardous search-and-rescue and disaster recovery scenarios to build good will and give the students experience. This has not been cleared yet, so it's mostly talk at this point.
This is about 10-15 years down the road, so about where the current XU faculty is now. Feel free to bring whatever character over, just keep in mind that while the Institute would have more advanced courses than a typical high/secondary school, characters are probably going to have much more general teaching job (like "science" or "history") than they would have teaching university.