"like Newcastle, in that you can sit in the lounge and watch it all play out whilst sipping coffee..."
or a beer!
I was forcibly stopped by a CE passenger entering group 1 lane at LHR because he thought I was pushing in.
In fact the queue of G3/G4 people had blocked his view of the empty G1 lane.
I find most airports the same, no control of priority or groups.
I've never seen anyone turned away at the point of scanning/presenting their BP because of wrong group.