Trying to use the Center Parcs wifi with an Amazon Fire Stick doesn’t work out of the box, it prompts you for a login page that disappears.
I got this to work but it is not easy. The way these login pages work is they register your MAC address (your wifi card has a unique ID known as a MAC address). If you have a linux laptop (& maybe Mac / Windows but you would change your MAC address in a different way if possible) you can clone the MAC address, log in with your laptop and this opens up the connection for your Fire TV.
Here’s how I did it:
Get your Fire Stick MAC address & turn off Fire Stick