The Aardvark House was closed around 2016, I believe? It is now a blank spot on the map and was ambiguously referred to by its historic name as Small Antelope House recently.
Malayan tapir - They were replaced with Brazilians. Malayan tapir are rare in the UK, only 3 zoos currently hold them whilst the Brazilian species are common.
Takin as mentioned above.
Arabian sand cats - Not a well known species but I always noticed a positive reaction from visitors due to the cuteness factor.
Not a specific species but the reduction in the cat collection. The cat species currently held are Amur tigers, snow leopards and servals. This is a zoo that at one point held lions, tigers, leopards, jaguars, snow leopards, cheetahs and several smaller species of cat a the same time.