The IPv6 addresses we get from BT are dynamic, but provided you are not rebooting the router too often, they'll only change occasionally.
Personally, I do have IPv6 & IPv4 DDNS set up on a personal domain with multiple hosts. But to do that I'm running a custom script on a third-party router, with my nameservers delegated to Dynv6 DDNS.
I only learn by making mistakes and owning up to them - boy do I learn a lot!
