Hi Solent Richard........read your review with interest as we were aboard the Preziosa a month before you , 21st January. Our reflections were somewhat different although I would agree that Marie-Pierre and Summit were excellent, they were our butler and restaurant waiter as well. We were fortunate to stay in 15031 just up the corridor from you, next time try to get one of these large square cabins as they are 50% bigger than the one you had, we even had a sun lounger on the balcony as it is so much bigger.
I would double check that your Virgin flight from Gatwick to Barbados was a charter. Our MSC / Virgin Flight was a Scheduled flight (VS029/VS30) as MSC this year were taking a block of seats not the full allocation. It is important as you will be able to claim Virgin Flying Club Air miles which we did, Premier gave us 8432 air miles (worth about £125).
We cruised Preziosa last year as well and the difference was astonishing, for the worse. The quality of the meat in La Palmeriae was extremely poor and like yourselves we dined in Butcher's Cut where the meat was superb but boy-o-boy did we all suffer in the YC restaurant, even 'Summit' advised us not to have many dishes as the complaints were endless.
The Gazebo you mentioned was erected due to the complaint about the food on offer at the One Pool during our cruise. You benefited from the change of YC Directors, the new YC who change midway though our cruise (Thierry Fnu) made many changes which improved the situation. The problem is you don't know which YC Director you are going to get, some are a disgrace to MSC.
We also booked for Yacht Club 2021 and have subsequently cancelled, just not worth the money anymore.