They will probably ask you the more obsure stuff or things that have recently changed to see what your level of attention to detail is and whether you keep your knowledge current. I work for a different TOC and the recruitment for instructors seems to change with every intake. We had to do a small ten minute presentation in the interview on a rules subject of our choice (from three choices), a few obscure traction/rules questions and they asked us to draw a map of our home station and explain all possible moves. A few years later they had prospective DIs do a project before the interview. Other interview questions were along the lines of "what would you do if..." scenarios (uncooperative trainee, struggling trainee, old hand driver returning from LTS, gobs***e on a safety brief, etc).
DI is a very different job to 'just' driving, you will learn a lot about yourself and others!
