We have been on many of the p/o cruises and are going on the ventura in august also QE2 BUT GO BACK TO P/O EVERYTIME EXCELLENT.
Any would be good but from personal experience Celebrity and Royal Caribbean sailing from Southampton/Harwich it depends on budget celebrity is a bit better for service if you let your agent know they can make arrangements for a cake ect on your anniversary day book a large table if going by yourselves.
Whats yor problem,the world is your oyster,once you have been on a cruise you wont go back to 2 weeks in spain.Any decent travel shop will give you all the help you need.enjoy!
Go with p&o arcadia ventura oriana oceana are the ones we have been on and they are excellentand will do you a cake if you wan.
Depends when/where you want to go. For me. back to back caribbean in March on RCI was brill. Best thing to do is read the reviews section of this sit.