A short illustrated book where a child discovers some sort of bootlegging operation, except they’re smuggling bars of chocolate, not booze.  And the smuggling is being done by giant alien hats.  The clearest image I have is the cops who end up busting the criminals. They took the form of white pith helmets, with twin gun barrels on their undercarriages.

I’m not convinced that this book isn’t a product of my childhood imagination, but the memory is pretty vivid.  I would have read it in the 1980s, probably in the UK or Australia.  The illustrations were painted, not line drawings, and in colour.