I have just got a EX520v router. Working well on IPv4. But I am having trouble setting it up for IPv6. My ISP is Hyperoptic. There seems to be a lot of advice on the internet, but most of it is over three years old. There is a TP-Link article, but that applies to a different model, and I don't see how to modify those instructions to make it work. The general manual doesn't seem to be clear enough. I can try messing around with various settings.

But at present I can't even see how to save settings so that I can come back and check things. The manual says to go to Advanced > Network >Internet, enable IPv6, and fill in relevant details. Then configure LAN ports and click Save. But when I do that, I just get the same LAN ports page back again, and when I look nothing seems to have been saved. Also I note that the IPv6 WAN connection says No Available interface. So what amy I ding wrong? There may be something very simple that means that my IPv6 settings just aren't saved. If I could get past that, I could try adjusting settings.

Any advice would be welcome, but specific details would be best.