I have tried setting up port-forwarding and DDNS on my BT Smart Hub 2. I was successful for 2 ports, but am struggling to get port 80 working as this is serving the BT Smart Hub 2 Manager page (not what I intend to do).
Any help or settings that I have missed to set this up properly?
I guess you are accessing port80 from within your LAN rather than accessing via your public IP address using 4G rather than your own wifi.
Since I saw the other topics regarding NAT loopback, I made sure I tried on my mobile connection as well. Same problem though, while other ports function as they should.
What is the actual problem you are experiencing, the hub manager is not accessible via your public IP address so the fact it uses port 80 shouldn't be a problem. You could try a factory reset of the hub and start again.