LHR to BCN Last Friday: We were in group 4. BA staff had not removed the sign from AA separating the queue into groups 1-4 and 5-9, so most people were in a single long queue as they probably did not know much about BA groups and the fact that there are only 5 groups. So the staff had to be turning people away all the time (some of them complained about the signs saying groups 1-4 and 5-9). The staff boarded groups 1-3 together and then 4-5. This made me wonder why they don't just have 2 groups: priority and non priority, instead of 5, making things easier for everyone. Bad organisation from BA I'd say.
BCN to LHR last Sunday: We were in group 1. Staff at Barcelona did seem to be checking boarding passes and organising people into different queues before boarding, although I got the impression that there were only 3 queues (group 1, groups 2-3, and groups 4-5), but cannot confirm it.