I am not a TA, but can sure speak to using Princess and their air. You should price the cruise and also get a price for Princess air (with transfers). Than, check the on-line prices for the air (doing it yourself) and compare! Keep in mind that transfers can be a hassle in England since the ports are located quite a distance from London. Another option with Princess is to use their custom air department which gives you options on choosing your own flights (you do have to pay the difference). We do a lot of European cruising (leaving tomorrow to catch the Brilliance of the Seas in Barcelona) and often find better deals doing our own air (this is true for tomorrow's trip where we got a great price from Aer Lingus). But, I can emphasize to much the transfer issue (particularly if you are new to Europe). Princess often uses Southampton which is accessible via the train from London, but that can be a hassle when you have lots of luggage.