https://www.polygraph.org/assets/docs/Misc.Docs/PCSOT_Model_Policy_March_2018%20.pdf
I've never seen this linked here. I looked through it and it seems like a goldmine of information for PCSOs. The most important thing I noticed in this document is that it explains exactly how relevant and control questions are structured and what topics they will ask about on each type of test on page 8.