Thanks fof the advice.
I visited the AFCO over a year ago, whilst finishing the PhD, they told me I would be too old by the time I joined, even though I was the correct age at the time of enquiring.
I recently finsihed the PhD and looked into it again. This time I'd heard about an age waiver and asked about this. The AFCO concluded that I would be over 2 years too old, so said no.
I just wish they would have mentioned the possibility of an age waiver the first time I visited.
I will call OASC and also write to the group captain as suggested and let you know how I get on.