Delayed is one way of putting it, but there's never been a set time frame for it. I do know it's still part of long-term considerations and is being discussed by officials, with the consensus being they certainly need to move it further South, but even once planning starts proper it would take a few years. The Mappins are likely to be renovated first from the information I know, and that will only happen once the gorillas, capybaras and potentially north bank works are completed.
It must be said, the current entrance is at an especially poor location with the gorilla works cutting off the main path to Barclay Court. I have a suspicion they may make the new entrance a priority just because of that.