After months of calling there is a cancelation on the QM2 with Cunard cruises. They have one kennel available.
I believe both dogs will fit comfortably (happily) in the kennel together. Cunard agents disagree - they have repeatedly told me that the dogs will spend most of the day in the kennel for a whole week. So, karlin and others who are familiar with boarding, especially UK standards:
Both of my cavaliers are on the small end- Guinness is 16 pounds, of a kind of lanky build, thistle is 13 pounds, petite but proportionate. The kennel is 30" wide x 35.5" deep x and 24" high. they will receive 3 walks per day, and there are visiting hours each day.
My dogs regularly share a 24" x 36" kennel in the house, and also when boarded. They get along famously, shared food bowl, no problems there.