I know it was quite a while since this topic was mentioned, but i am new to this site.
I purchased a centre armrest from E-bay a few months ago, and most of it is sitting in my boot now

As pointed out before, the nut which holds the passenger side of the bracket was too short, so I ended up using a file to make the bracket a bit thinner...this worked, and the nut connected properly

Once I had fitted the bottom bracket, it was time to attach the main armrest, but the metal internal part is way too far to the right, and does not connect to the bracket (it looks like it needs a spacer or something?)
Anyway, as I modified the lower bracket, I cant send the thing back now

Has anybody else had this problem?  My cars a 2001 1.8T 3-door with Recaro seats