The Examiner Handbook is not the place to look for pre-course entry requirements. You only have to look at Instructor Form 1 completed by the FIE on the initial test to see that the CPL knowledge requirement must be entered at item 8.
http://www.caa.co.uk/docs/33/FORSRG1131.pdf
There is of course a situation (App 1 to JAR-FCL 1.300) where holders of a non-JAR-FCL licence with instructor rating can qualify to teach for a JAR-FCL licence by completing the FIC cource and passing a test with an FIE. They need ICAO CPL knowledge but not JAA CPL knowledge. It could be argued that such a person by virtue of holding a JAR-FCL PPL has disqualified themselves from App 1 to JAR-FCL1.300. In any event they would not qualify for a FI raing on the JAR-FCL PPL.