Again, there are three oneworld lounges in Terminal 3: British Airways, Cathay Pacific, and American Airlines. While there’s really no reason to visit the AA lounge, the BA lounge is best if you care about alcohol. I’m not a big drinker myself, but others have told me that this lounge has by far the best selection of liquors.
This lounge is also pretty sizable with a number of different seating areas. Make sure to explore before committing to where you sit. There’s also a small dining room at the far end of the lounge.
The lounge is an odd combination of self-service and wandering servers who will bring you things. They have menus floating around the lounge, but there’s also a self-service buffet as well as a dining room. I’d probably check out the buffet first to see if that suffices for you and then try asking someone for things off the menu.
I don’t think the food options in this lounge are any better than the Cathay lounge. The buffet is a bit larger, and there seems to be more frequent turnover of food, but the selection of items seems more limited to me. In the mornings, it’s a pretty typical English breakfast spread with some more egg dishes on order.
Overall, if you want to drink, come to this lounge. Or I guess if you really want kippers or porridge. The lounge is large and can accommodate a lot of people, and it has a designated play area (not pictured here because kids were using it when I visited and I didn’t want to look like a major creeper). On the other hand, the bathrooms are not the cleanest, the food is pretty meh, and the lounge agents seem more interested in watching cricket than serving.