BEagle,
There is a difference between not needing to have a rating and actually having one and keeping it valid.
As for R Examiners, one that I am thinking of would be illegal if they performed any form of flight instruction because they do not have and never had an instructor rating. They are not a ground instructor.
All they have is an approval from the CAA which authorises them to sign off ratings that are revalidated by experience.
Please reas the appropriate standards document which explains all this very clearly.
Regards,
DFC