> especially as it seems everything is 2001::/16

I was sort of expecting that this week.

I had to transcribe a v6 addy for a WAN-WAN test (a few mi apart).

That's when I noticed that Charter (Spectrum) had issued

   2603:: for one WAN and 
   2602:: for the other WAN.

ref: https://bgp.he.net/AS33363#_prefixes6