Fred Olsen offer Fly/Cruises on Braemar departing from Bristol.
I presume that you are talking about Fly/Cruises? Only joking, though you can actually join a few cruises from Falmouth if that appeals? Birmingham is the nearest main airport to you, after London, used by most of the larger cruise lines for flights to Europe and the Caribbean, but I know that Thomson fly from Bristol to many of their Foreign Embarkation Ports. Maybe they will have a cruise that you like the look of? Happy cruising.
P&O have some Caribbean departures from Cardiff if thats any help for you.