I reached the B gate just before general boarding started at LHR, so no idea how it went at the beginning.
At ATH they take it easy and boarding was not even announced in the lounge when the Final call was flashing on the screens and people boarding. There was something I assumed was fast track and which I used, but again no idea if it really was a fast track and how it went at the beginning or after boarding was finally announced in the lounge.