@mrbrown 

What is the status of the "Internet" LED on the AX3000? (green, orange or off)

Have you previously had another router that was working fine with your Chorus fibre connection, before you got the AX3000?

If yes, check the Internet/WAN settings of the old router and then apply those settings similarly to the AX3000.

In case this is a newly installed fibre connection, have you already checked if another device, for example a computer hooked up to the ONT via Ethernet cable, can successfully establish a connection to the Internet?