And the signature for the biennial training flight for revalidation of the SEP class rating gets written onto the back side of the license (App. 1 to FCL 1.1075), which as an instructor I can refuse to sign if I am not happy with the applicants performance.
According to App 1 to JAR-FCL 1.075, only an Examiner or the Authority is permitted to sign the revalidation process. An Instructor is not so authorised.
Appendix 1 to JAR–FCL 1.075 (continued)
Instructor ratings and SE piston class ratings may also at the discretion of the Authority be revalidated in
the licence by the Examiner who forms a part of the revalidation process. If an Examiner is not involved in
the revalidation process, the rating entry will be made by the Authority.