Believe it or not, but the improved, enlarged, glass-fronted bear exhibits in 1987 were actually fairly good for their time, considering the RSCC only recently built a similarly-sized enclosure for its Sun Bears. Colchester held one elderly Syrian Brown bear, and the pair of Asiatic Black bears at the time these new enclosures were built.
To the best of my memory, they were built on the site of the two existing, smaller, wire bear cages that had previously housed a group of (all syrian?) brown bears on the left, and the black bears on the right. I think the other brown bears had all died out leaving the lone female by 1987. I think the new enclosures took in some of the sloping goat paddock to the right of the original bear cages, the remainder of which was used for the new sealion pool (now penguins) down the path.
The behavioural problems evident in the brown bear especially I would suggest came from a combination of spending years in the previous cages, and the fact that the new glass-fronted exhibits marked the advent of the end of visitor feeding (bags of pellets to feed the animals used to be available up until the early 80s), and therefore the bears couldn't spend their time begging. This is not to say that Colchester didn't attempt to enrich their environment with old christmas trees, scents etc, but it just wasn't enough to prevent the stereotypic behaviour all of the time.