Looking at the mood boards online, I'm particularly interested in what is planned for Phase 3 - it seems that a large area (in the original plans for the National Wildlife Conservation Park, this area was earmarked for both Tanzanian savannah and Nepalese grassland areas) will contain European bison, Przewalski's horses and red deer, if the accompanying images are to be believed.
I wonder if they will be in a more nature reserve-type setting (similar to what is happening at Wildwood). It certainly doesn't look like a series of smaller paddocks is planned for the area.
It seems like this overall plan may have been the direction of the zoos for a while, but I definitely get the sense that the schematics and plans were thrown together quickly (due to their vagueness the lack of answers on the collection). Phase 1 seems to be fairly fleshed out, although I doubt any plans have been drawn up at this point. I doubt much thought was put into phase 3, as much as deciding on what areas of the park will be developed for it. I hope they can eventually whenever this phase happens move the giraffes down to this area, creating a larger Africa zone, but this obviously low priority.