It would be very difficult to cut along the length of the steel angle, most vertical bandsaws can't cut 3mm steel and a horizontal bandsaw/ chop saw often dont cut very straight and couldn't cut down 150mm taking off only 2mm. Why not just redesign a bit to use 25*25mm angle to save a whole lot of machining.
The way I'd do it is to put it in a milling machine. How many 150mm lengths do you need?