I was a bit unsure about how to proceed with the last part of question 2 on the 2005 paper and also the last part of question 1 on the 2010 paper.
I have read your solution to the sample paper in the book (which is q1 of 2010) and I'm still not quite sure what's going on.
The (100) direction is along the x-axis, right? In which case, I don't see how a 90degree rotation around (100) is equivalent to a translation of (1/4,1/4,1/4) - surely the x-coordinate would be unchanged?
Likewise, in the 2005 question, it is really really hard to see the symmetries!!!