Mayhem at Wicksteed - May 25, 26
Try any of the model railway suppliers. 00 scale 1:76 but humans come in different sizes so the difference is not worth worrying about.
Try looking up 'Preiser"figuresMost model railway shops should have them.I just cannot find any 1:50 current Australian Navy figures.
Preiser do various scales and era's so you can get modern and older style sets. The big thing about Preiser is they are damn expensive for the amount of figures. For instance a 5 person set could set you back £20, so 4 quid for a 1:72nd scale figure Phew! They don't do naval types but in the civilian range you can get various railway or farm figures using tools that won't look out of place - think platform staff in tunics and peaked hats, make suitable officer types for ww2 scenario.
For some reason most model figures are actually to 1/72nd scale, I suspect because the main manufacturer, Airfix, wanted them to match their railway scenery kits. Model vehicles tend to be 1/76th scale including Airfix ones. I don't know why this is. https://www.scalemates.com/kits/?akamai-feo=offhttp://www.plasticsoldierreview.com/Index.aspxBoth of these sites are really useful in finding the right stuff to match.