Surely the FI course (and CRI course) is about learning how to teach, not a refresher on some of the basic handling skills as Mr Bose suggests? If you don't have the basic handling skills yourself you shouldn't even be considered to start the course. A naieve view perhaps but it's got to be true.
Similarly, the ground school part of the course should be on how to deliver pre-flight briefings and teach any aspect of the theoretical knowledge requirement of the the PPL syllabus (just in case a student needs your help understanding something and asks that awkward question). The course looks to be pretty intensive, so remedial training in basic PPL theoretical knowledge shouldn't be part of instructor training. If all experienced pilots with PPLs who aspire to instruct really knew their stuff, CPL level of knowledge wouldn't be required. I assume however, that the people in the JAA and CAA doubt that the average PPL has ever attained and retained this depth of knowledge (honestly - can anyone here deny that it's possible to pass the PPL multiple choice theory exams by reading the confuser and without really understanding big chunks of it? ) Hence the requirement for CPL knowledge to become a PPL instructor. Don't get me wrong - I'm all for PPL instructors. But I'd hate to pay good money for instruction from someone who doesn't really know what they're talking about.