I can guarantee they do! Three in the UK do not use CGNAT and many people are using this service to connect back into their home routers using the public IP or DDNS. The public IP will allow direct access back into the home router. I’ve already proved this with a borrowed LTE router in Bridge mode.
All I need to know is what settings I need to set on the AR150 to allow connection back inside the LAN using the public IP I have.
The problem at the minute, as shown above, is that the USB modem isn’t passing the WAN IP address to the AR150. It’s getting the LAN IP address. When I tether the iPhone, the AR150 gets the WAN IP.