You won't get an external IPv6 address on your WAN port as it's not provided. The routing is happening on the LinkLocal addresses.
Also, if you know of people that are having problems, I'd be interested to hear about it. I don't know if there are issues on the network (I'm one step removed from the IPv6 broadband rollout, but kinda working on bits of it), but I'm happy to raise any issues internally to see if we can get them sorted.
Matt
Edit, Oh yeah, I'm a network designer at BT, probably should have out that at the start.