[3] His father was killed in a wharf accident when Alan was nine, and his mother, a Cockney from London, died a few months later.
He was educated at Perth Modern School, leaving at 15 after failing to complete the Junior Certificate.
[4] In November 1949, Seymour returned to Sydney where he became an educational and freelance drama writer for ABC Radio and later television.
[2] In 1965 his play Stockbrokers are Smashing But Bankers Are Better was withdrawn from broadcast on ITV in 1965 due to concerns over its sexual content.
There Seymour wrote a novelisation of The One Day of the Year, and another novel The Coming Self-Destruction of the United States of America, as well as stage plays and magazine articles.
From 1974 to 1981, he was a script editor and occasional producer with BBC Television, after which he returned to freelance writing.