Complex sentence: He attended Tiffin Boys Grammar School in Kingston-Upon-Thames where he became Head Boy of the school in his final year, he later went on to return to the school as a part time drama teacher and judge school events such as House Drama.
Split into simpler sentences: He attended Tiffin Boys Grammar School in Kingston-Upon-Thames where he became Head Boy of the school in his final year. He later went on to return to the school as a part time drama teacher and judge of school events such as House Drama.