OK, Vector801...
First and foremost, and I tell you this from personal experience - if you care more about being a pilot than an officer, and I don't say this to discredit the RAF (I was in it and chopped as a pilot) then join them. This is NOT what the AIB want. They want you to be keen to be, and able to be, a good Royal Naval Officer first and foremost. The pilot part is a long way off. Divisional work, and a hundred other things which are vital to life at sea come first.
If I were you, and I hope you are successful, I'd make this very clear. There's an awful lot of time at sea when you're not flying on an FF/DD tour, as I'm sure many far older and bolder than me will attest. You really need to want to be in the mob beyond just flying. Also, being an Observer is an outrageously challenging role. So much so in fact that of the 11 or 12 on my entry at Dartmouth who got as far as the BOC, only 2 made it to OFT and I believe one has been recoursed. There's a reason for that - it's damn difficult. Don't discount it out of hand.
Best of luck to you - hope to see you around the Andrew some time.
BL