All - looking for advice from those more experienced than me at travel through LHR. I am arriving LHR in F on AA and will depart in Y on Air France (separate ticket). Questions: - Will I have to go through immigration in the UK? - Will I be able to make use of arrivals facilities? Lounge options? - How long should I allow to get from AA/lounge to the AF flight? - Any changes to any of the above when I make the return journey (AF to AA)? In both cases I will have about 3 hour layover. Thanks!