Garry was born in Kingston upon Thames, UK. He studied at Brunel and Nottingham Universities for a first degree in Applied Chemistry and subsequently a master's degree in Food Science. Garry worked for Mars Incorporated for 28 years, but since retiring in 2008 he has been pursuing a lifelong interest in the Napoleonic Wars, which began in 1973 when he started wargaming the period. In 2009 Garry had an article on Denis Davidov published in First Empire magazine and then self-published his first book in 2011, Wellington's First Battle, about the Battle of Boxtel in 1794. Based on this research Garry also had a series of articles published in the Smoothbore Ordnance Journal relating to British artillery in Flanders 1793-5. In 2018, Garry also published a small booklet summarising three years of research into the 24 men recorded on the WW1 memorial in his village. His passion is to bring the smaller or lesser known actions to life using quality archived based research.