Think it's in the circled area on Lvl 1 (link for pdf)Can’t see it anywhere. It must be next to the unicorn stables and the bunyip enclosure.
Maybe on Lvl2 as well, the seats look different, could be railing with cup holders? In a similar area to Lvl 1 (actually pretty sure it's continuation of what is shown on the Lvl1 plan).
This shows the Lvl3 plan, I think it's pretty clear that the Lvl2 section on Moorabool st will be where the standing room is, if anywhere at all. It looks different to the seats above, below and to the side of it.