infact whether cpl knowledge expired (theoretically not in real terms) was the very question i asked of a school
LASORS H1.7 has the answer (as will CAP804 when it becomes the official replacement). That's part of what I would normally cover with a lapsed FI before they test with a FIE, ie not only going over a bit of practical & theoretical instruction but also covering any applicable changes as well as exploring the general scope of what they would be eligible to teach. ATSOCAS has been a good one so far!!