Yes, that's right. If it's a revalidation by experience then it simply gets written on the little green ratings insert in the holder's licence. Only instructors who hold a valid examiner rating (could be RT, Ground Examiner, or Flight Examiner) are authorised to sign the reval.. .. .If it's the biennial training flight then this is signed off in the log book. No words are necessary other than 'BTF' followed by your signature and licence number. Any current instructor can carry out the flight and sign the log book.