Bushes for the rear trailing arms aren't that different but the tubes are shown separate on the superflex pic, these are inside the oem ones as well.
Bushes for the front arb, if he says center I guess he means those, the other ones are those in the front trailing arms as per your 3rd post, seems like the correct P/N as well. ARB diameter of the front arb should be 23,5mm indeed.
I'd consider replacing the front arb rings on each side of the control arm as well, originalle they have rubber on them and it is likely that rubber is gone now. The rubber helps close in the control arm more to prevent shimmy. I even went one step further and added the old rings to the new ones to close in the control arm even more for sharper steering, goes well without any clunks or side effects. Pic:
