Hold the rotor in a vice, undo the 24mm nut off the rotor shaft and remove pulley and fan. Then, either press the rotor out through the bearing with a press or, hold the rotor by the slip ring end, with rotor between a vice's loose jaws and the end plate resting against the side of the jaws, and belt the rotor out through the bearing using a soft faced mallet, thus allowing access to the screws in the retaining plate. The second method takes a bit of practice but is extremely effective if there is no access to a press. If it won't budge, it may need a few hours soak with some wd40 or similar. Good luck.