Complex sentence: He was educated at St Ronan's School and then at Charterhouse and Lincoln College, Oxford, where he became friends with John Betjeman, drew cartoons for the University magazine "Cherwell", and developed his trademark upper-class persona.
Split into simpler sentences: He was educated at St Ronan's School and then at Charterhouse and Lincoln College, Oxford. At Oxford he became friends with John Betjeman, drew cartoons for the University magazine "Cherwell", and developed his trademark upper-class persona.