Definitely agree with the previous suggestions, especially natural makeup, take out any piercings beyond one earring in each ear. (You can certainly have the other earrings, but take them out for the interview and you would need to take them out when working with the Cunard guests).
Also, do you have a good dark-colored business suit? A suit with a knee-length skirt or pants for ladies and a conservative suit and tie would be perfect. Cunard has a tradition of British heritage and culture and it would be wonderful to wear a dark suit with polished shoes or modest heels would be entirely appropriate.
Good luck and definitely let us know how the interview goes for you....