Of flamingo land I remember very little other than seeing an elephant, i'm fairly certain they had no whales or dolphins at that point, or I expect i'd remember them too.
Blackpool I remember quite well, I remember the sealions in exactly the same enclosure they're in now, the gorillas and orangs in the same enclosures, but the gorillas did not have access to the island. I remember the current elephant enclosure had a fence down the middle, and whilst one half was used for Asian elephants, the other half was used for giraffe and white rhino. I remember small mammals in the elephant house, stuff like tree shrews and kinkajous and possums etc. I very vividly remember American Bison in the enclosure opposite the zebra.
Of thrigby I remember the swamp house, big black gibbons, the tiger enclosure with raised walkway and a row of aviaries with Snowy Owls and a big Hornbill in. I've not been here since, so I don't know how or if it's changed.
FLAMINGOLAND - I visited it in the bad old days of the early 1990s, there was only Jangoli left as the other Asian elephant had died, the dolphins had only just left, there were 1.1 Polar bears with 2.0 cubs, the male Polar bear was in with a single Brown bear, adjacent to the female and her cubs, though separated only by bars, there was a large herd of Wapiti, vast numbers of Peccaries with many young, a pair of Sooty Mangabeys, Stump-tailed and Toque Macaques, possibly Bonnet macaques, Andean Condors, blackbuck, timber wolves, caracals, and chimpanzees in the old cages and the sunken Island which looked like a pit (the dominant male I think had just died in the moat when the group were introduced to this part just before I went). A keeper took me into their house to show me two adult males separated from the rest of the group and kept indoors.
BLACKPOOL - Visited in the late 1980's, remember Arabian gazelle with white storks, wallaroo, chamois, Markhor on the island, gentoo penguins where the common otters eventually went, hog deer, pileated gibbons and spider monkeys on the monkey islands, the small mammal house with Quokka, ground or possibly even spotted Cuscus, and North American porcupines, other marsupials I can't remember, quite possibly tree kangaroos. Twycross and blackpool seemed to aqcuire an amazing range of unusual marsupials at one point together, which gradually died out over the decades. The ground cuscus and the odd wallaroo seem to be the remnants of this.
THRIGBY HALL - Visited around 1987, then 1997. Early visit saw generic leopards, snow leopards, blackbuck in paddock on site of swamp house and sulawesi enclosure, Indian Crested porcupine, smooth-coated otters, pygmy tree shrews, the original crocodile house was a greenhouse leaning against the courtyard wall, where the moluccan cockatoos are now, it housed the mugger crocodiles and a hog badger.
In 1997 the site resembled the current layout, although the amur leopards hadn't arrived and the forest house was not yet built. There was quite a sizeable breeding flock of painted storks and the Owston's civets had not yet arrived.