Sorry it has taken so long to respond - we had a fantastic time!.
The beginning of the trip to Ngorognoro Crater, as you already mentioned this is a must visit. The landscape is stunning. We managed to see pretty much everything including a black rhino. Both places where we stayed were excellent. As we were the only ones there at Plantation Lodge we were upgraded to a larger apartment/house. The food here was very well prepared, the staff extremely friendly.
I thought the first two days would be difficult to top, but our stay at Legendary Serengeti Camp was truly exceptional. Again we were the only ones there, so we had free reign of the entire camp. The fact that you can go off-road takes the safari trip to another level.
Here we saw no other vehicles (albeit it is a quiet part of the season) and we managed to get very close to loins, cheetahs, wild dogs and a plethora of other animals. Our driver Godson was first class - very friendly and knowledgeable of the animals and plants in the area. The food here was first class, with an extreme attention to detail.
Arriving at Zanzibar, even though we had a nice time, it was probably the low point of the trip. Even though the hotel was nice and clean, the food was not very good (IMHO) and (as you mentioned) the beach was not up to scratch and was littered with plastic and other debris.
Luckily though we did spend the last few days at Fanjove. Again we were the only guests! We had the whole island to ourselves. It was a small slice of paradise. Waking up in the morning, going for a quick dip in the ocean before heading down for breakfast was pure bliss. We spent our days snorkeling and lazing around in the sun. We helped move a turtle nest and also took a dolphin trip - where we were lucky enough to see over 400 of them in one (or more pods) around the boat.
Overall we had a fantastic time during the Safari and beach. Thank again for all your help!