You're probably unaware that Derby even had a zoo, but it did. A very special zoo, to be honest, and it just wasn't a success. Derby's specialty was being the worlds first autopsy zoo. Whenever an exhibit at another zoo died, Derby stepped in and offered an autopsy service, with the animal pelt being restuffed, and set up as an exhibit.
For example, here we have Oggie (ex London Zoo) and Trevor (ex Dundee Wildlife Park) the non-breeding pair of Polar Bears.
With hindsight, the failure of the zoo after just two years shouldn't have been a surprise, especially after a hot summer. Predictably, the Petting Zoo was a total flop.
Bonus - Breakfast Nightmares. Damn, it's gone now.