Hi Rob, my 2 vintage 50's bikes came equipped with the standard Raleigh drop handlebars of the time, usually Maes type (e.g. Reynolds alloy) or Reg Harris Road Bend (chrome steel). For pre war one name that comes to mind is Lauterwasser, I understand that they were fitted to top end racers at the time including Raleigh, and they seem to be half-drop, as suggested by your father.
Re the brakes, must admit I agree with Woz: I have found that steel rims where the chrome on the braking surface has partly worn off, and with surface rust, are better for braking.
In my experience I find that the braking surface on stainless steel wheels or new chrome wheels is too smooth and shiny, and especially in the wet ... can be scary !!