ANNEX A: Assessing whether an EEA national who claims to be a student or self sufficient person holds Comprehensive Sickness Insurance
Chapter 9 on appeals provides a bit of information in that context at point 3.4 on page 10, which is not new.
This may be of some interest to those affected by the requirement, unfortunately there is no further HO guidance on the issue since they started enforcing this rule, in many cases without regard to NHS eligibility.
If anyone finds more official policy/guidance information, please let me know by PM.
For information about providers and member experiences with policies and EEA applications, see Providers Of Comprehensive Sickness Cover