 In 1965, Illingworth was invited by the Council of the College of Physicians, Surgeons and Gynaecologists of South Africa to give the 1965 Louis Mirvish Memorial Lecture.He was also invited as a distinguished guest to the 45th South African Medical Congress (MASA), and was made an Honorary Fellow of the College of Surgeons of South Africa.Illingworth travelled abroad again the following year to receive the Honorary Fellowship of the Royal College of Physicians and Surgeons of Canada.