Simple Port Forwarding Hub 5 Not Working

@jeffas I am experiencing the same problems as everybody else at present. To my knowledge, it is a Hub5 device that I have here, but the software version is entirely different to what you are reporting there. Does your Admin -> Info page look anything like this?

It appears from this that the router has no public IPv4 interface, though I am being given a specific IPv4 address consistently from any 'What is my IP' sites that I visit. Is that an IP address of some other node within the VM network though perhaps?

I have set up a couple of port forwarding rules to forward traffic to the Asus ZenWifi router I have behind the VM router (and for the Asus router to forward that onto the applicable servers behind it. If I connect to the VM Wifi, I confirm the forwarding rules on the Asus router allow traffic in, but any attempt to get to them from the public internet using the IPv4 address I found is not working. I have also tried connecting to the router's IPv6 address via a browser (eg. https://[ipv6address]:12345) but it times out.

Last of all, I'll be knackered if I can find any option in the router configuration to switch to modem mode. Does anybody know where I can find that? Although I would prefer to keep the VM router in router mode, I don't need its Wifi, so could switch to modem mode if it allowed the incoming traffic properly.