I am not up to speed on current happenings but, as an erstwhile Wing Commander Cadets at DIOT, I can add that the system allows cadets at Cranwell to submit a branch change application whilst still undertaking IOT. I had many cadets seek them during my tenure, mostly those trying to avoid Boulmer because the chop rate was so high! The way the system worked when I was there was thus:
Cadet submits application in good faith; cadet gains interview with sqn cdr who provides current policy statement; cadet accepts that and gives up or cadet insists he/she wants to continue; cadet gains interview with Wg Cdr who explains policy again, but cannot stop the cadet pushing for his branch change at that point; application submitted; application rejected cadet remains in allocated branch or application accepted (normally only if there are extenuating circumstances) and cadet goes to the bar with a smile on his face.
The bottom line is, however, that appointments to branches are allocated based on quotas (requirements) per annum. If you apply for a branch change in the same year that the quotas are already filled then you are on a hiding to nothing. Consequently, the best time to seek a branch change is, if you're lucky to be at Cranwell, when the quotas for the following FY are being established. If not, if there are no extenuating circumstances (eg medical that existed when you attended OASC, but has cleared up - and you can prove it) you will be out of luck.
Otherwise everything that has been said before by people who are closer to the coal face than me now, will undoubtedly also hold sway.
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