Should there be bushings on rear suspension mounts?

I've been getting a really bad creaking and groaning from the rear end. I stuck my head under the back end and had someone bounce on the bumper and I think I have located the source...
There is a bolt at each end of the suspension arm that the coil springs sit in that is connected inside the crossmember in the back end. It doesn't show in the picture, but the end that is bolted inside the crossmember is twisted and I'm trying to figure out if something is missing from them. They just move freely, grinding metal on metal with no bushing of any kind that I can see, or it is there but so perished it might as well not be there.
Hopefully the pics give a good enough reference. Again, this is in the back, the suspension arm that runs from the wheel under the coil spring and sits inside the main crossmember. Thing is, if I have to get bushings, I don't know what part of the car this is...is it a rear suspension arm maybe? Something like that?
Also, to replace the bolt/bushing at the wheel end, do I have to compress the coil spring, or could I just stick a jack under there to put a little pressure on the spring enough to remove the bolt and replace the bushing? I suspect I'll have to compress the coil spring because this suspension arm has to drop low enough for me to push in the new bushing.
Thanks for your help
Kev