This is a case of Clarkson46's signature being spot-on!
The fork type separators will always do damage to something, I gave up on them decades ago. If you can't get hold of a large enough separator of the hinged variety then use the oldest method about, this has never failed me in 30 odd years, trucks included.
1. Remove the nut, clean the thread so that the nut spins on easily and replace the nut to the point where it binds on the self locking bit. This will protect the thread and prevent the parts flying off to the four corners of the workshop when the joint lets go.( this applies to using the hinged sepator tool as well)
2. Set things up so that the joint is in a state of slight tension, ie it is trying to pull itself apart. Depending on the orientation of the joint you may need to put a jack under something and slightly compress the suspension.
3. You will need a metal block like a dolly (a 2lb lump hammer works well) and a reasonably heavy hammer (1lb ball pien or similar).
4. Hold the block like a dolly against one side of the YOKE of the joint and with the hammer strike the opposite side as if you were trying to squash the circle into an oval. This needs to be done smartly, ACCURATELY, reasonably hard and with confidence.
When you get this right you will find that the joint just pops apart. The secret is: use as big a hammer as there is room for, and hit it once.
WARNING: Mind your wheel arches! also brake pipes and other dangly bits not to mention fingers.
If you have access to such things, an alternative to the hammer is to put an old riveter head or similar into an air chisel and put that against the side of the yoke. There is less likelyhood of 'collateral damage' this way, but a big hammer is still the best way with big joints.
When you are reassembling things put a jack under the stub axle carrier to push the taper into the joint, this helps to stop the threaded part turning when you get to the self locking bit. Again, if you have one available, use an air driven impact driver, like in the tyre & exhaust places, they run the nut down so fast it doesn't have time to turn the thread. A lot of ball joint threaded studs have an allen hex or flats on the end so that the stud can be held until the taper grips the yoke.
On VWs don't forget to check the alignment of the camber/castor adjustor in the top arm.
Good luck!
Mechanics are easy, all you need is confidence, a good eye and a B****y great hammer :lol: !