According to Sutherlands: "Phil mounting rings can be used to mount Shimano cartridge brackets. This makes it possible to .... Remove the Shimano cups using a vice and a rubber mallet." I interpret this to mean that you set the vice jaws so that the cup is resting on them but not touching (or barely touching) the sleave that the bearing is in. Then smack the spindle with a mallet. It should pop out pretty easily.

I am guessing that your problem is that the parts are of mixed parentage. They should fit, but they just don't work together. Sutherland's also says: "Peugeot cottered spindles and cups do not interchange... bearing diamater is much smaller..."