I have now completed all the Lighitng & Rendering 2: Mental ray tutorials. Overall, I managed to complete them with no problems and they were all very interesting and fun to do. The only slight challenge that I had with this tutorial is that I couldn't find the "Get Brush" tool straight away.
I have completed both parts of the motion blur tutorial, with the arm batch render being in a video and the octopus, with some images showing frames at different shutter angle settings. Very straight forward and simple, so I had no problems with this one, except for Maya freezing when I changed the number of divisions in the Octopus when smoothing. I added the arm motion several times due to how fast it was.
I've left this tutorial incomplete for a while now and so I have finally got round to completing it. The top image shows where I had left it and the bottom image shows the final render - as you can see. I didn't have any problems completing the tutorial.