More data points today:

LHR gate A7 0725
Nothing announced. The gate agent came over to start letting people in the group 1-3 tensa. Didn’t say anything about which groups he was boarding, but when he saw my 0 he sent me to the side to board with the pre boards. So a success I think.

LHR gate A11 1250
This was a bit of a mess. Slightly late running flights, lots of pre boards as there were quite a few families with young children. (EDIT: also not a lot of room around A11 due to the work going on in that area). When the gate agent came to the front of the group 1-3 queue and opened it she called group 1. I asked about group 0 and got the response that she “hadn’t been briefed” but she changed and called group 0. Was one other person also who was in front of me so I used him as a battering ram thro the crowd, and I successfully blocked the group 1 trying to tail gate him and go in front of me.

BHD 1500
Nothing here - although I have heard reports from others they have announced for group 0 to come forward once in the corridor. Door opened from the lounge as usual and they were scanning bps straight away, followed by a wait on the jet bridge.