We were on Deck 3 in May & it was certainly not a noisy deck, I think you will be fine, Enjoy your cruise...
Being located far aft on deck 2/3 the noise and vibration when the ship was at full speed is deafening and one would be well advised to book a midships or slightly forward cabin. So you could have a noisy passage unless the weather and the waves are good to you.
Sorry ....but you are frightening these people quite severely. Deck 3 is 5 decks above the waterline and seven above the propellers. Last time I was on QE2 we reached a very high speed and I have been in her in very rough waters and never found her to anything but good in all waters. Unless there has been a marked turnaround in her seaworthiness I wouldn't worry ... Neil.
We were in cabin 3015 in June cabin lovely and quiet, and very handy for the lift that takes you up to the rear entrance to the Mauretania Restaurant