hi debbie,
i would suggest that the guy standing up was a steward, given the "S" inside the star on his left arm and the high collar on his tunic. as to which service?......the guy stood up could have been in the royal navy. as to your father, very hard to make out the emblem on his buttons plus the black/dark tie could have been royal air force.
not much help i must admit so may be better advised by trying the royal naval assocation,plus those of the royal air force and even the royal marines.