Thanks for the replies.
TopBunk - I'm perhaps being a bit slow here, but what do you mean by "from the other side of a glass door"? Are you referring to the shuttle buses that you take you to/from the aircraft?
I confess I picked 1.5 hours at random. Does it actually take longer to turn around a B747?
So, I guess the only colleagues you would bump into at the hotel are those who are not flying the aircraft back that you just landed, but who are returning to London on an earlier flight than your return trip? If that makes sense.