Well, the person in Rahnee's photo appears to be a General Officer (Staff Tabs and General Staff hat badge) with Medals : 1914/15 Star, British War Medal, and Victory Medal with MID Oak Leaf, Volunteer Decoration, and a slightly obscured medal that looks as if it could be the Croix de Guerre. Around his neck is the insignia of a KCB and centrally beside the row of medals is a seven pointed "star", the insignia of the KCMG.
All of this fits with it being Sir John Monash, unless there is another WWI General of similar appearance and awards.
Perhaps family memories were confused ??
Maec