McCauley prop overhaul
Under FAA regs it is ultimately down to the aircraft owner but a maintenance organisation can make recommendations, and if a real airworthiness issue can report the aircraft as unfit to fly. However, with EASA registered aircraft, it is completely out of the owner/operators hands and you have to carry out inspections as per the manufacturers recommendation whether it by hours/cycles or as in your case, calendar time regardless of hours. Your part M maintenance organisation/CAMO will be able to clarify this for you.
Hope this helps