Yesterday, after arriving at Gate A11 for Flight 1496 from Heathrow to Glasgow, the gate agent asked us to wait for a moment, and after the crew boarded, my friend and I were invited inside the tensa.
After we waited for a bit, they clearly called Group 0, and after a few calls, they called Group 1 and the other groups in order.
The good thing was that only Group 0 and the pre-boarding group that needed help were invited inside the tensa, so the actual boarding process was really ideal.
They didn't open the tensa until we boarded. I really appreciated how they handled it!