Having never visited Basildon, Southam or any of the others mentionet i cant say however they all look/ sound horrible. Glasgow was picked on a lot aswell and some of the enclosures at Dartmoor were very bad, actually no, a lot of the enclsoures at Dartmoor were bad.
The worst zoo i've visisted though is a zoo which i dont think a lot will have heard of. The Animalarium at Borth, it's been a while since my visit since i only visited once for obvious reasons. The collection was of fairly common zoo animals. Lemurs, Capuchins, Monkeys, Parrots, Llamas, Domestic Aniamals, Racoons, Reptiles, a small cat species and probably a few others aswell. Tiny enclosures especially for primates, the cages and housing was so tiny it was unbealiable. Visitors were also allowed to feed animals. There was a set list of which animals to feed and which not to. Do you think the public listened?
Off course not and lemurs and monkeys were begging for food throughth cage mesh. Awful place.