I made the walk through the gate (23) and back through arrivals on Saturday. The bloke on the passport check asked where I had come from - "here" was enough to get me through.

Interesting they use a particular gate, we all went to gate 23 but as we queued the screens went blank, and ba.com reported the flight as cancelled. I guess they were expecting that to happen as all the luggage was already going around the carousel after the short walk there.