You're right about the bushes being bonded into the wishbone - and probably about burning the old ones out - Henry could tell us as he has a set, probably with instructions - Henry?
The ball joint is on the other end - if this is worn, you're wasting your time replacing the bushes. For best results, you would need to get the bushes out of a new arm and replace them.
I'm beginning to wonder if it's all a waste of time - during the average 155 ownership, you're only likely to replace the arms once, and at £38 a side, it's not a big deal. And you get new ball joints into the bargain!
To top it all, I've been speaking to a Land Rover owning friend of mine, a vehicle which is notoriously good at eating suspension bushes. He's been told that fitting 'firm' bushes moves the suspension play and vibrations elsewhere and can cause fracturing of other componenets / welds. What to do?!
There's always one - and it's usually me!