Following World War II service as a Merchant Navy radio operator in the North Atlantic, Selwyn-Smith joined Myer Zang's Modern Packages where he learned sculpting and plastic moulding from 1947-1949. Hethen joined Willmore & Sons that made moulds for lead hollow cast figures for Timpo. Selwyn-Smith used his wife Mary as a model for a figure of a woman leaning against her suitcase.
In 1951 Selwyn-Smith formed Selwyn until his backer committed suicide and the moulds were sold to W. Britain.
Returning to Zang, he developed the Herald Miniatures plastic figures with Zang that Britain's distributed from 1954 until the firm was purchased by Britain's in 1959. Selwyn-Smith also developed Britain's Swoppets where figures could be assembled and combined with pieces of different coloured plastic to form a variety of poses that was patented in 1956.
- Cole, Peter Obituary The Guardian, 5 August 2006
- Improvements in or relating to model figures - Patent Review GB19560014389 19560509