For the initial two sets I would get some 25mm square bar for the axles and some 14mm plate. Then take it to a local blacksmith and get him to drill and tap the M12 holes. Then heat and bend the bar to shape. Bending has the benefit of being stronger because you are keeping the grain of the metal intact, rather than cutting through it on a mill. Also you aren't wasting material/money by machining a bigger bit of material down to size and shape.
Then if your happy with how these parts perform they can either make you a batch the same way, or make you a form to go in a press. Whichever is the cheapest option.
I wouldn't personally go down the CNC route on the axle. Only on the plate part when you want a batch of them.
Hope this helps.