Ivan Hall, the architectural historian, who has died aged 93, was a leading authority on Georgian architecture and a fervent campaigner for historic buildings. Born at Withington Hospital, Manchester, on February 13 1933, he was the son of Joseph Henry Hall, a Yorkshireman whose engineering career took him to work in Nigeria, and his wife Ethel. Ivan was a precocious pupil, winning a scholarship to Manchester Grammar School, where his interest in architecture emerged. He set out to visit country houses within bicycling reach. At Tatton Park, near Knutsford, he impressed the owner, Lord Egerton, who encouraged him to join...