Having talked to a guy that completed the 'final board' last year I think their minds are pretty much made up when you go in for the interview it is more of a one way thing than a two way conversation. That said just make sure that you come across as a keen to learn, but flexible with it. But that is something you have already done to get through selection and aptitude testing.
HTH
ps
don't mention the lack of AH QHI's at wallop or the delays in the AH program or the aircraft gathering dust in Shawbury, or the empty hangar at Dishforth, and you'll be OK.......maybe
