Originally Posted by
Gardyloo
The AA arrivals lounge is landside at T3 and most certainly has showers. However it's not a Oneworld lounge; access is only to those coming off premium cabins on AA metal. Same goes for the BA arrivals lounge at T5.
Both of these lounges are open to AA and BA Emeralds arriving on a longhaul AA or BA flight at the terminal in which the lounge is located, in any cabin. There may be additional entrance priviledges also; There is a thread in the AA forum with more details.
As for T3, the AA showers are probably best, then BA for food, and CX for peace and quiet. The CX showers are pretty good too. Skip the BA showers. Due to the tasty noodles and higher quality champagne, I usually head to CX. If you have kids, then BA is the way to go.