I stayed in and fished out of the Inn at Robert's Grove in Placencia a couple of years ago. Guide's name was Eworth Garbutt i believe. They own a small private island out near the reef with wade-able flats on one side and deeper water on the other. His older brothers guide somewhere north of there, but i don't recall where.
It was a great hotel, and the fishing was spectacular, even if we did end up having to outrun a nasty thunderstorm one afternoon.
I believe the place mentioned above is Cay Caulker, and in Belize they pronounce it "key" not "cay," if memory serves.