I am Australian. My father fought in the Pacific Islands in WWII. He used to tease me, when a child, with what I considered to be a 'Forces Alphabet' i.e. a mental exercise dreamed up by soldiers in the trenches.)
Obviously my supposition was wrong and this alphabet was based on the Cockney alphabet, perhaps half-remembered by 'New Australians'.
The variations I remember are 'C for Ships', 'I for E' (Ivory), 'K for Dinosaurs' (cave for…), 'N for eggs' (hen for …), 'O for a nice cup of tea!' and 'R for Askey (Arthur Askey)'. More might come to mind.