I came back on 138 just over a week ago and this was my experience.

Arriving from domestic on the transfer bus there was less of a crowd but the normal bunch of 'assisters' to be ignored. I headed for the emptiest door and then for the BA desks at 'B', so may have missed the BA greeter. No problems picking up a paper boarding pass and no longer an exit immigration form. No sign of mossies, either.

Security and immigration had fast track for 'business' and were pretty empty but the usual 'check you have the stamp' queue was there - so some things never change!

The 'lounge' was down a floor in an unused gate area. There was a reasonable range of hot and cold snacks, a serviced bar at the end of counters (which wasn't immediately visible) and WiFi. Not as good as the old BA lounge but a lot better than some - see other thread

Overall better than the old T2 experience. It will be interesting to see what the new lounge is like when it opens. And how long the 'bright and shiny' terminal stays that way.....