I appreciate it's against the grain on FT - especially for a self confessed genius - to read and attempt to comprehend a thread from the start, but to summarise, the situation is that the passenger will likely arrive before the pick-up.

We have collectively ascertained that the area immediately outside domestic arrivals is small and likely to be crowded.

As such, the better solution is for the passenger to head somewhere else where they can 1) get a seat and 2) if required get a coffee while they wait.

The mezzanine level is fine for this. IIRC, there's also a Cafe Nero (I think) down the escalators outside the International Arrivals zone.

However even with the best will in the world, waiting and looking avidly through those doors to domestic arrivals for someone who has already arrived (& wandered elsewhere in search of a seat) is likely to be a fruitless experience.