You can find a guide on overhauling the rack here;-
https://www.theminif...l-uk-type-mkii/
In your case, is the rack still fitted to the car ?
If the rack is still mostly assembled, there is a tool I made (based off a factory item) that can pull the bush with the rack assembled (and on car). It's a thin wall tube that is a neat fit over the inner rack and has a tapered thread on one end and a through hole on the other. You'd start off by winding the rack all the way over to diver's side, then put the tube over the inner rack and screw it in to the bush, hopefully it will get a decent grip in to it, then putting a rid (phillips driver is good) through the hole that's cross drilled through the tube and wind the rack back the other way, it - hopefully ! - pulls the bush with it. Sometimes the small steel tube that the bush is fitted in to is stuck firm, and no matter how hard you might try, this just won't work, at this point, you need to disassemble the whole rack and put something through from the driver's end to bash it out, again, this is possible with the rack in the car.
I'll try and remember to post up a photo of the tool a little later.
This technique is fine if the rack is otherwise in good order. You can replace almost all other parts of the rack with it fitted in car, however, the upper pinion bearing is one part that you'll struggle (read: won't) be able to remove, if you find you can, then the rack body is distorted or worn and the whole rack needs to be replaced in any case.