The ship sailed from Tilbury, an hours tube and train ride from London. We stayed two nights in a hotel near Paddington Station and took the District Line tube from Edgeware Rd. to West Ham. There we transferred to the C2C railroad for the trip to Tilbury Town where we were met by a free shuttle bus to the pier. It cost 10.50 pounds each, you can buy tickets at Paddington in the Rail info office. They were very helpful. The ship was originally to have left from Greenwich, so this was a less convenient port.
My husband and I travel light with one rolling carry on suitcase and a tote bag each, so it's easy to take a train and we don't worry about the airline losing our luggage. The travel lecturer on the ship arrived with no suitcase and waited ten days for it to catch up to the shop. If you have several suitcases and can't manage on the tube and train a taxi would cost about 65 pounds, we were told.
We bought day passes for London Transit for 5.20 pounds each ( a good value since one ride is 4 pounds.) We visited the Tate Modern, St. Paul's Cathedral, just across the Millenneum Bridge. We enjoyed the Grace Kelley wardrobe show at the Victoria & Albert Museum and the Turners at Tate Britain. The British Library is another must see to view a copy of the Magna Carta among other treasures in the exhibition hall.
Great weather in London, too, it was perfect for walking the shopping areas near Harrod's and riding the red double decker busses along Regent's St and into the City.