I visited C and D in central Oxford today. Both hives are building comb. They were both very calm so I didn't need smoke. I just gently opened each hive up and took a look.
Neither hive have any brood yet, so there's no way to be sure whether they have AFB.
I didn't see the queens in either hive.
C was populated before D. The bees are building in the super, which is unwelcome but expected. There is lots of new comb partially filled with honey. They've building toward the front of the hive (shown by the wax drop on the hive floor).