Davey147
I have done several ICAO conversion courses for FI's as a FIC instructor (and BTW I hold all the FAA Instructor ratings, as well as the South African CAA Instructors too).
Mostly it is not a quantum leap for most motivated FI's to convert.
Unfortunately they (the CAA) will only issue you with a restricted FI after you have done the 15 hour conversion course - this applies to well qualified personnel from the RAF, so no exceptions. However, we have been told that an employer (flight school) may write a letter after you have been doing some instruction at the establishment asking for your restriction to be lifted without having to do the 25 solo sign-offs.
PM me if you need more info
Porridge