They is nothing excessive in using JAR-FCL, LASORS had and CAP 804 has no legal basis as a standard against which to conduct an audit.
The question is, what kind of facility are they auditing? If it's an FTO then it is subject to Appendix 1a to JAR-FCL 1.055, irrespective of the course(s) that it offers. If it's a Registered Facility then it is not subject to Appendix 1a and the requirements for theoretical knowledge instructors contained therein do not apply.
I would take issue with Whopity in his statement that Appendix 1a relates only to training for professional licences - there is nothing in JAR-FCL to support this contention. The confusion may arise from the fact that in the UK this issue never arose as the CAA (outwith the requirements of JAR-FCL) required an FTO offering PPL training to also be a Registered Facility. This was an effort to save resources by ignoring PPL training, arguably with fatal consequences.