UPDATE: I've now been told that an FI(Microlights) may conduct the SEP refresher flight training in a Microlight but will need to know the revalidation requirements in Schedule 8 or FCL.740.A and follow the relevant AMC/GM. An FI(M) cannot hold FCL.945 privileges, so could not sign the Certificate of Revalidation for a Part-FCL licence holder. But if the FI(M) has 'R' examiner authorisation, he/she could sign the Certificate of Revalidation for a UK ANO licence holder.....