My method above works well.

Put the smaller socket onto one side of the bush (this socket should ideally be very slightly smaller than the part it is being pushed out of , in your case the rear arm) put the larger socket the other side of the bush place it all in the vice and tighten , thus pushing the smaller socket through the arm ,removing the bush into the bigger socket .

If this dont work , buy a blowtorch from the local hardware store and heat the bush/arm up first

HTH