My best guess is:
One of the other banks that got their designs implemented included a +1 arcane circle.
I think it might have been Chesapeake.
Cue the whining on Uhall, because:
a.) "They have something we don't have".
b.) A bunch of the shards still don't have their designs implemented.
And, it looks like the devs capitulated, and dropped a circle at every Brit Bank, without story or context. Or, I'll add, a new bank design to actually attract people back to WBB.