Though the exteriors of Brompton School are in Oxford, the school quad is several miles to the east near London in Eton. The quad of Eton College is used for this location.
Long before Harry Potter was filmed in Oxford and Sherlock was a popular TV show, Steven Spielberg and crew visited Brasenose College and Radcliffe square for a movie called “Young Sherlock Holmes”. Brasenose is used as “Brompton School”, which does not exist. Other location throughout England were used for filming.