Dr Warren Feeney has referred to him as "alongside [David] Low [...] undoubtedly New Zealand's most famous international illustrator".
[1] His school career appears to have been successful: "He was a member of the first eleven cricket team and a scholar in English, Chemistry and Latin, as well as a regimental sergeant-major of the cadet corps and head boy in his final year.
[1] Colvin volunteered for World War II, initially training as a commando in Australia before being conscripted into the Second Expeditionary Forces (2NZEF).
The latter has been described by Ian F Grant as, alongside Gordon Minhinnick's Soldier Sam, New Zealanders' 'best-loved cartoon characters' during the War.
[3] Colvin emigrated to England in 1956, having become 'increasingly frustrated with criticism of his work by senior staff at the Evening Post' and, more generally, with the stifling environment of 1950s New Zealand.