From LASORS (my bold type)
A QSP(H) who has held a AAC (limited) or a
restricted* Green (or Master Green) helicopter
instrument rating within the 5 years preceding the
date of application for the IR(H), is required to
complete a minimum of 15 hours IR training at an
approved FTO, of which 5 hours may be in a
FNPT 1 or 10 hours in a FNPT 2 or flight
simulator
Outside the 5 years would require completion of the full 50 hour course.