My only experience on a British ship was spending a day on the carrier they had in the Arabian Gulf in 2000 (I think it was HMS Illustrious, but maybe HMS Invincible - it started with an "I") when I was the SubOps guy on the Carrier Group SEVEN staff aboard USS John C. Stennis (CVN 74). I rode over on the helicopter with my Admiral, worked with the submarine guys on the British ship planning a Combined exercise (including an American submarine officer who was permanently assigned to the British equivalent of the Strike Group Staff), and flew back the same day. My fellow staffers were upset that I got to go, because they figured it was a wasted opportunity for someone to drink while at sea. That's still my only helicopter ride.
Have you ever cross-decked to an allied vessel? (Alternate topic: Haven't the Brits ever heard of temporary racks for the guys who have to sleep in the torpedo room?)