Weren't gorillas supposed to be in the development that didn't occur and is now replaced by Islands.
I wish they would get the chimp genetics sorted and start some breeding, or even just have one baby,
All I know is that some years ago(in the Nineties) when Chessington WOA was going through one of its periodic threatened shutdowns/changes of ownership and the animals were going to leave, that Chester wanted to get hold of their successful breeding Gorilla group and were prepared to build an enclosure for them. Unfortunately it never happened and all of Chessington's animals stayed, including the Gorillas. It would have been good indeed if Chester had been able to have them, instead of them still living in rather mediocre accomodation and adjacent to a giant funfare.
Re the Chimps- one problem is where they have a large multi-male mixed group like Chester, how do you control the breeding so that only 'pures' are born? It would mean presumably doctoring the males so only a pure male could still be fertile and father young.