Just finished fitting control arms to both sides of our 53 plate Jazz, and found the following - luckily I had the use of a two post car ramp that made life a lot easier, but still took more than a day to do.
1. Ball joint castellated nuts - one side totally seized, the other side just came off as it's supposed to.
2. Undid the 32 mm drive shaft nut on the seized side but totally failed to free it from the hub, despite some serious blows with a chunky copper faced mallet. How hard do you have to hit these things to get them to shift?
3. By undoing the two bolts on the chassis end and dropping the control arm, I had just enough space to get a 1mm stainless disc cutter disc in and cut off the top of the seized ball joint bolt and nut, which undid very easily after that.
4. Used a "tuning fork" type ball joint separator to separate the ball joints, but it did require some serious thumping before they popped. Not sure how well they would have come apart using the classic "thump them on the side" method. Those ball joint separators will wreck the rubbers, but in this case, new ones were on the control arms so no problem there.
5. New control arms are a bit fiddly to slide into place, but then they just seem to glide into place and you wonder what all the fuss was about when they do.
6. But the biggest problem I encountered which wasted the most time, was me not realising that the M12 nylock nuts which had been supplied with the control arms had a 1.5 mm pitch while the threaded section on the ball joint had a 1.25 mm pitch. I reckon I wasted 2-3 hours trying to get the nut to tighten up because I was assuming that it was the nylon insert that was making it hard to turn, where as it was actually the nut trying to go cross threaded.
Monday morning I got the right nuts and the job was a doddle after that.
Moral of this story - never assume, never trust anybody and check everything!!