Craven combined film with naturism. In the 1950s/60s nudity in film was taboo but he evaded censors by not showing pubic hair. As a result, he became a pioneer in this genre. Under the pseudonym Michael Keatering, Craven directed the naturist film Travelling Light (1959). This was the first naturist film to receive public release in the UK. Described as an underwater ballet, it was shot off Corsica and released in 1960. He later produced Sunswept (1961) and Eves on Skis (1963). He lost a lot of his film archive when a tree fell on the garage in which it was stored while he was away at his apartment in Costa Natura, a naturist resort in Málaga, Spain.

Craven with his wife Christine set up a company to produce the lamps, naming it Crestworth. Operating from small buildings on an industrial estate in Poole, Dorset, Crestworth has supplied the world with lamps since 1963, changing its name to Mathmos in 1992. They were a commercial success through the 1960s and early 1970s, and became a symbol of psychedelia. Craven said, “If you buy my lamp, you won’t need drugs… I think it will always be popular. It is like the cycle of life. It grows, breaks up, falls down and then starts all over again.” In the late 1970s fashions moved on and lava lamps fell out of fashion. The Walkers kept the company going throughout the 1980s but in a much smaller way.

In the early 1990s, a young couple began manufacturing and selling them successfully. Cressida Granger and David Mulley approached Craven and took over running the company and renamed it Mathmos in 1992. Initially they were in partnership with Edward and Christine Craven Walker and the company was called Crestworth Trading Ltd. Over a period of years they bought out the Walkers bit by bit.

Walker was a member of Spielplatz naturist camp in the 1950s. It was at Spielplatz he met his second wife, the popular nudist model Elizabeth Elcoate Gilbert, who was routinely described as Naturism’s Ambassador. He set up his own naturist resort at Matchams, near Ringwood, known as the Bournemouth and District Outdoor Club (BDOC). The camp closed in 2000 after Craven’s death.

Toward the end of the 1990s, Craven suffered from cancer. He died in Hampshire in 2000, aged 82, and was buried in a small cemetery in the New Forest.

Astro lamp has been in continuous production for 50 years and has been handmade in Britain since 1963. and is still made today by Mathmos in Poole. The Mathmos lava lamp formula developed initially by Craven Walker in the 1960s and then improved with his help in the 1990s is still used. His lava lamp company Mathmos celebrated its 50th anniversary in 2013.