I think Belfast's breeding of Spectacled Bear was due to having a compatible pair long before Chester ever did, and not related with the enclosure design. So a long period elapsed before they(Chester) were in a position to breed them.In contrast the enclosure at Belfast zoo is excellent, affords visitors uninterrupted views and affords the Spectacled Bears there their privacy too, conditions conducive to breeding, they had a cub at Belfast before Chester, hence Chester marketing their birth as 'First on the UK mainland', rather than 'First in the UK'.