I wonder if its easier done with all the suspension off the car?
On R5s (and I suppose an R4 will be very similar) we used to get them up in the air so the torsion bar was at head height and then go at it with big hammers and a specially made drift. It still took hours and hours! Good exercise though!
If you put a lot of penetrating fluid on everything before hand then it might help free everything off.