Clyde Hannan left a comment about a school friend of his, Ben Decker, who lives in Transkei. As far as I know he isn’t related, but it prompted me to start a page for the Decker family on the family Wiki.
Val’s grandmother was Emma Decker (1900-1980), who married Joseph Theodore Christopher Chelin in Bulawayo, then Allan Dudley Greene, and finally Ed le Sueur. Her grandfather, August Decker, came to South Africa with the British German Legion in the 1850s with his wife Mary Nevard Morton, whom he married at Colchester, Essex. They had one son, Edwin Robert Morton Decker, and he died a few years later.