Hi Tonks!
Why not suggest to your UAS studes that they buy (shock horror) their own civil log books and keep their chocks away-to-chocks under times in them - and take them with them when they leave!
Incidentally, ALL UAS time DOES count towards a JAR-FCL PPL, contrary to what some rubber-desk Johnny blotter-jotter at the CAA (where do they get these incompetent functionaries?) told one of our recent students.......