I've read this thread, and some other stuff, and my head is spinning. I'd like to know what lounges I could -- and should -- use given the following.

Flying on AA from LAX-LHR in First with a 3 hour layover and connecting LHR-STR in Club Exec, using an AA First Class Award. I have no status on BA, but am Plat on AA (and thus Sapphire on OW). Thanks for you help.

xlax