hmm, so it seems likely that it must have been in the same block as the curassow aviary then. I will bow to your deductive reasoning. Looking at the aerial photo again it seems almost impossible that there was viewing of the block from the rear (it appears to back up completely against the boundary), but I think you can see the keeper passage running through the middle (entered from the curassow end, as seen by the safety porch in the curassow photo). It looks like there's about three or four aviaries in the back part. It's hard to make out, but there may also be aviaries down the side as well (at the opposite end from the curassow) - is/was there a section of path there for visitors? Looking at the curassow photo you can see rear viewing would have been impossible in 1992 at any rate, because the back wall appears to be a fake-rock one, and the shrubbery at the side looks far too dense to admit any viewing at all.