I agree, even 40 years ago Bristol's Ape House was many decades out of date. To be fair, the bars of the cages (indoors and outside) did give the orangs the opportunity to climb a little - the concrete bowl type of orang exhibits in other zoos were even worse.
I believe this house(obviously not the Gorilla extension built on the end) was originally the old Lion House, before it became an Ape House. The Orangutans used the outside cage previously inhabited by the famous Gorilla 'Alfred'.
Always been interested in how the old pair of Orangutans, Jack and Jill, only ever produced this one baby late in their life, though Jill was a good mother to him.