My husband and I cruised Golden Princess to the British Isles. It was our first Princess cruise and first time to British Isles. We are experienced cruisers with other lines and to other destinations, including Europe.
Consider booking early. Our ship was fully sold out weeks before the cruise -- in part, perhaps, because only this ship and maybe Crystal did this itinerary this year.
We arrived in London 2 days before embarkation and stayed in the Renaissance Chancery Court Hotel. Very large room by European standards and very modern with dual sinks and separate shower/tub. Caters to business travelers but treats vacationers well. Breakfast was pricey (20 pounds per person), primarily due to low value of the dollar. There is a nearby McDonalds.