It was my connection so yes I just showed up. When I saw the gates named for my flight I went there and was told no, you have to go back from where you came and go through security and then come back here. The train said it was full and had to walk for a long, long time and to me, it was very confusing, along with some other folks who also had to do the same thing. I would have thought the BA flight crew might have helped a bit more. Sorry you sound as though it's not allowed to be confused. I had a 2 hour layover and it took all of it to get through to my gate.