The following portion of the linked report explains it reasonably well:
A few days prior to the park opening, our Director received an email from East Herts Council Planning Department suggesting the zoo had no planning permission and needed to close. A retrospective planning application was submitted using a local planning consultant and was refused on the grounds of the Wildlife Park being built on green belt land.
I really hope that they can either relocate or (preferably) continue where they are. It's a great little collection with an eye on the unusual and the owner is truly passionate and quite welcoming to us enthusiasts. If it were to go belly up then it would be like losing a great collection before it had even started to get going.