I don't think BT Infinity supports IPv6 yet

Thanks, but according to this article http://www.ispreview.co.uk/index.php/2016/11/bt-broadband-lines-now-support-ipv6-internet-addresses.html they do

BT have indeed now completed their rollout of IPv6, Sky completed theirs a few months ago. I had a similar issue with a TDW8968 on Sky which would actually give me an IPv6 address but had no actual IPv6 routing, My earlier post here got no response. I have since moved over to one of Sky's own routers which works fine. It would be good if TP-Link worked on getting their routers working on BT and Sky whose implentation of IPv6 differs in various aspects from those used elsewhere.

Have you followed this? http://www.tp-link.com/en/faq-857.html

I'm on an Archer vr900 and IPV6 on BT is working fine.

Yes, thanks. I'm leaning toward it being a BT problem rather than TP-Link. If I completely bypass the router and connect PC directly to a Huawei HG612 modem I only get a Link Local address rather than a Global IPv6 address.

That's unfortunate, as you are no doubt aware as soon as you mention to BT support that you aren't using a HomeHub they roll out 'we don't support blah, blah, blah' although I have found if you can get a referral from the BT Care team on Twitter to the Irish support team they're quite good and more knowledgeable than the usual 'support'

Thanks, I'm a regular contributor on the BT forums so am aware of the team. Not overly bothered, it was just an academic excercise really to see if IPv6 was working. It might be an individual problem, but I suspect the BRAS I'm connected to isn't fully enabled for IPv6 yet. I'll leave it until the new year and see what transpires. Thanks for your interest.

A quick update to this thread if anybody is interested. It would appear that TP-Link devices do not support /56 Prefix delegation which BT use. I believe they are working on a fix for later models but not sure at this time if the 9980 will be included.

Just resurrecting this thread, to say there are rumours that beta firmware is being produced to implement /56PD IPv6 for the TD-W9980

I recommend you to contact to the technical support team. You confirm whether there has a beta firmware fixing this problem with them.