Pete, you need a big hammer and a drift
. I use a nice square edged punch as a drift. Support the steering head on top of a saw horse or the likes and then drive it out with sharp blows. Move the punch around the bearing race to keep it square as it moves out. The lip on the race is quite small so your punch needs to be nice and square - not rounded and abused! You need to hit it really hard to move it initially.
Installing the new bearing is easier if you chill it in the freezer first. I grind the old race down slightly using a bench grinder so it is no longer an interference fit in the steering head and then use it as the drift to drive the new bearing in. Use grease to help. Once the bearing race goes in below the steering head I then use a large socket as a drift and drive it all the way home. Good luck and if you keep the bearings greased and adjusted you should never have to do this job again