Re: RAF transfer
I know of several RN officers who have transferred without going through IOT, but they had been on exchange as fighter controllers for lengthy periods beforehand.
Hopefully there is someone on here from Cranditz to provide truth, but I suspect that if said officer had completed Sandhurst and initial professional trg satisfactorily, the main requirement would be to complete the SERE (Special Entrant and Re-Entrant) Course, if that's what it is still called, which lasts just a few weeks and is aimed at providing those who have the requisite skills with the additional knowledge required for service in the RAF.