Complex sentence: Their leader in fashion being Harold Acton, their later leader in intellectual matters was more noticeably Maurice Bowra; their attitudes are those portrayed and parodied in the nostalgic "Brideshead Revisited" of Evelyn Waugh, the most important literary figure to emerge from them.
Split into simpler sentences: Their leader in fashion was Harold Acton, but their later leader in intellectual matters was more noticeably Maurice Bowra. Their attitudes were those portrayed and parodied in the nostalgic "Brideshead Revisited" of Evelyn Waugh, the most important literary figure to emerge from them.