Barry, I have done this a couple of times and found the best way to get the old ones out is using a hand held hacksaw blade, the small one with the blade exposed and cut the bush in half top and bottom, if necessary, if you happen to hit the case, it's not a big issue.
Never had any trouble drifting a throw out bearing onto the carrier with a soft hammer. The bearing being on a vise and taping on the carrier, use some grease on both and clean it off when finished.
Wayne