Trustpower Fibre to NetComm Wireless NF18ACV to Google Wifi set up help

So I'm having real trouble getting the Google Wifi set up with the existing network in a place I've moved into. We have Fibre with Trustpower that goes from ONT into the provided modem which is a Netcomm Wireless NF18ACV. Fine if you a near the modem but the house is big so struggles to cover the place.

I have three Google Wifi units but I just can't even get the first one connected. The annoying thing is, it isn't even failing in the same place, sometimes it is because it will keep telling me the ethernet cord needs to be plugged in, other times I get past that and go through naming the network and setting a password, only for it to fail at "finalizing your WiFi network". Telling me that something has gone wrong and looks like they lost contact with the Wifi point.

So I have tried setting this up using both an iPhone and a Moto G6 android. I get further in the process with the Moto than I do using the iPhone. I've tried factory reseting the Google units, swapping out different units for the initial set up, as well as different (new) ethernet cables.

I had done some reading on here and Google about Bridging and tried that but honestly i'm not 100% sure I did it right and it didn't work anyway.

So I'm not sure if I need to bridge Trustpowers provided modum, if I have double-NAT that is stopping it or Trustpower uses VLAN tagging that won't allow it (or all of the above)

I am ok technicality and happy to give things a go but my knowledge is more Google-Fu and I'm just stuck now. Hoping I haven't just got some useless Google points.

Here is the modem information

Here is the WAN info

Happy to provide or answer anything else but would really appreciate some help to get this sorted. Thanks