Arriving LH to T5 can use AA Arrivals lounge in T3?
Have to wait for a colleague arriving in T3
according to the rules, it seems not, you must arrive to T3, but asking forum experience on this, is this enforced,
British Airways
You can enter the Arrivals Lounge if you flew on British Airways to LHR on a same-day, long-haul international flight arriving in Terminal 3 and are**:
Flying in First or Business Class
oneworldŽ EmeraldSM
British Airways Premier