One knows before one books a cruise on Britannia it is a large ship, that said very easy to get around we did not get lost once.
Our Cruise :- Thomson Dreamliner from Manchester, ample room in economy no need to upgrade, do though book seats IF you want to be seated together, pricey at £20 but worth it.
Good on board entertainment for the 8 hour flight, good dinner too.
We had a Port Side Balcony Cabin on 'D' Deck 11, Forward, very forward, in fact 3rd cabin from the front. Slightly smaller than Ventura, but still fine for us. Balcony is smaller too, cannot recline the seats too far, but one is not there to host cocktail parties. I enjoyed sitting out there.
Bathroom scores!!! a GLASS shower door, shower larger than average on a ship, good White Co toiletries.
Our cabin guy was just superb, helpful , courteous and always spoke when he saw us.