Peel the whites off the egg yolks. In a bowl, mash the yolks with the milk until you have a paste. Add salt, sugar, and the juice of 1 lime. Stir in the peanut oil a little at a time, then stir in the olive oil. Chop the egg whites and add them to the bowl. Stir in the fish. (this stuffing can be refrigerated for later use, or served at room temperature.)
When you are ready to eat, cut the avocados in half, remove the pits, and fill the cavities with the stuffing. Squeeze on a little lime juice and enjoy.
In Ghana, the dish is served with strips of red bell pepper or pimiento as a garnish. This is a nice touch. I also like it sprinkled with paprika and served on lettuce, along with wedges of lime so that each person can squeeze some juice onto his serving.