Regarding the Three Hours for Lunch Club medal, I have seen at least one example in bronze. There are (at arm's reach) two works about Tait McKenzie that mention this medal.
Tait McKenzie: A Sculptor of Youth by (1930) describes the medal and illustrates a plaster cast; despite the 1926 date, the caption attributes it to 1921. The chronological list of works by McKenzie does not seem to list the medal at all.
The list of works in The Joy of Effort: A Biography of R. Tait McKenzie by Jean McGill 1980 places in the 1926 listing and describes it as a cast medal.