in regards to question 2: m14 (the diagram says) should be a 22mm head flat to flat from what i have read. as loosening it, either use an impact wrench or its hammer time. i find a few love taps with a soft hammer on a bar will help loosen up seized bolts like these. as for the nut......... cold chisel and no i don't mean the band.
Germans: Why can't they make everything?
I fixed it up - the thread that holds the swaybar bracket was stripped inside. I removed the swaybar bracket supports (part number 12) and then took off the swaybar with the one "support" attached. I then moved it into a position were i wedged a scewdriver in there and used a spanner to turn the nut. I tried to cut it out with a wood chisel but it didn't break it. I used a thick washer on top of a new nut to support the swaybar bracket.