Two more data points.

LHR gate A1 for NCL
Not that I was earwigging () but I heard the gate lead say to the floater that there was one group 0. She came to the front of the group 1-3 tensa and called for any groups 0, so I went forward in front of a gaggle gathered around her. She commented that I was the first 0 she had seen. So worked ok.

NCL gate 3 (this is the usual NCL gate)
Aircraft had come in early so the door opened at about 30 minutes before and after the scan it was straight on, no waiting in the gate area. No mention of group 0, but then NCL has been and was today a pleasant experience.

I have BHD to try tomorrow.