Don't rule yourself out - let the doctors do it for you because that's what they're paid for. If you knee injury is sufficiently bad to preclude you from the military, do you think the CAA will neccessarily be willing to hand over a Class 1?
Scroggs beat me to it but....if you don't like discipline, join the RAF! From what I've heard even officer training is getting warm and cuddly these days (unlike the old days
).