Same experience as Bartinbrook, also in July. We had actually arrived on an AA flight (separate bookings, so didn't through-check) which is the far side of the airport and a bit of a hike through the central parking lot, then got told that we could have rechecked our bags for the BA flight back at the AA side of the airport where we arrived. By the time we were told this, it was no longer worth the schlep back again, so no idea if that's correct or not. Only saving grace is that the boarding is straight from the back of the lounge, which I hadn't seen before and thought was a great idea.