No signs of a fix for HH3 from BT as far as I can see.
Thought I'd relay my experience phoning BT to discuss the port forwarding issue.
The guy on the phone made it clear that while the functionality "might" be present in the router "it is not a supported feature".
When asked whether the router can be connected to remotely and the admin menus accessed he gave the same answer. If I understand correctly he also stated that using an IP camera or network device was not allowed by BT (illegal?) although that was later downgraded to "not supported".
When I said that remote access would be very useful so you can check that everything is ok (e.g. your family still has internet access) when travelling he laughed and said he didn't know or think anyone would want that service. Basically a put down.
Under more lengthy prompting he referred me to the (fairly well known) website
http://portforward.com/ and stated there "might be a solution there but we cannot support you any further".
It seems he thought my incompetence was the reason I could not get port forwarding to work but of course the real reason is that PORT FORWARDING ON BT'S LATEST HARDWARE DOES NOT WORK.
And by the way, he also demonstrated ignorance of portforward.com! portforward.com is not updated to work with HH3, only works with earlier BT routers as of a week or so ago.
So my impression of BT is that they are doing everything they can to make life difficult if you want to do anything other than fits in with their very narrow idea about how to use the internet.
God forbid anyone set up a home network and connect it to the internet!
