Honestly, I can not think of anyplace better than Ivan's, either. That would be my first choice.
On the Beach, Kuyaba would get my vote. However, keep in mind that you can not reserve the "tree top" table. It it first-come-first-served (found that out when I tried to reserve it for my wife's birthday, once). The Blue Hahoe at The Spa gets good reviews, but I personally haven't been there. The Rockhouse would also fit your requirements, but is not as good as Ivan's, IMO.
Just Natural is a great idea, but on the completely opposite end of the spectrum. No doubt they will be able to cater to your every need, but it will be in a rustic, wooded and casual environment. You will want to call ahead to make sure they have wine or any other special requests.