Originally Posted by
teemuflyer
If you're connecting at LHR, I don't know why you would like to use any Arrivals Lounge, unless the connection time is so long you have a chance to go into London proper for a meal, for example.
To access these lounges (AA at T3 or BA at T5), you need to clear UK immigration and then re-clear security to get back airside. Otherwise just use the F Lounge of your departing terminal for a shower and layover.
The showers at T5 (arrivals or departures) are grim, whereas they are great in the AA arrivals lounge.
I had a long (6 hour) connection recently so went landside to use the AA Arrivals lounge for a shower and breakfast before taking the HEx to T5 and BA Galleries First for my onward flight.
Admittedly with shorter or T3-T3 connection you'd be better off staying airside, particularly with the T3-T3 connection as the CX lounge showers are great.