So ... At the gate in T5 c they herd those on the list to the area where pre boarding people go, as well as them. That causes confusion and was very crowded.
You go towards the plane but wait at another holding area. Very British in they way the they wander round holding up your passport when it's your turn, occasionally calling out your name. You get swabbed. Hands, socks, electronics and then board. Hopefully that's a one off.