He was the son of G. E. Mannering (570) and brother of S. Mannering (2521) and J.E.Mannering (4677) and after attending Fendalton School, was in Julius House from 1938 to 1940.
After leaving College he joined the Royal New Zealand Air Force and was stationed at Wigram. When the war ended he turned his hand to working on a farm, selling insurance, and radio announcing before he finally settled into photography in 1949. He remained in this profession until 1985, taking the photography firm of Mannering and Associates to national and international recognition. During this time he travelled to Antarctica five times for the New Zealand Government on various projects.
He was lucky to have a close relationship with the Hamilton family of jet boat fame, and this gave the opportunity for several overseas trips, jet-boating various rivers, including the Colorado, the Mekong, the Sepik and the Zaire
Upon retirement from photography life became no less busy for Guy, he worked tirelessly for the Jet Boat Association. Photography threw yet another challenge at him with the dawning of the digital and computer age.
In 1996 Guy and his wife Margie moved from their home in Christchurch, to Geraldine in South Canterbury to be closer to the mountains they loved. His love of these and the outdoor life, which he inherited from his father, remained with him always. The ascent of Mt Cook being one of his more notable climbs. He also climbed several peaks with his brother John, in the early nineties to mark 100 years since his father claimed the first ascents. He was still walking and planning trips in the mountains with Margie and friends from Geraldine until the time of his death.
As well as finding time to publish five books, the last one released just before his death, he also studied music and learnt to play the piano, and then compose his own music, which he recorded on disc. Much of his music was dedicated to the back country and the mountains he loved.
He died in Timaru on 7 August 2003 and is survived by his wife Margie and daughter Leslie.