Originally Posted by number_6
I've only taken BA HEL-LHR (and AY LHR-HEL ... a flawed strategy) and traveling on BA does not allow using the longhaul lounge. Maybe AY is different. I think there was a security checkpoint between the BA gate and the longhaul lounge so it wasn't even possible to get to the longhaul lounge (without a longhaul BP). But it was early in the morning, and HEL makes for late nights, so I may not have been the most observant. I do remember being surprised at how bad the coffee was in the lounge, somehow I expected better.
Let's not confuse the longhaul lounge with Gateway Fresh Lounge. It's the same lounge complex on the non-Schengen side, but the longhaul lounge is to the right and Gateway Fresh is to the left when entering the lounge opposite gate 33. The admit policies should be the same for both regarding OW elites - Sapphires to the left and Emeralds to the right if on AY flight. This is how it used to be, but after my adventure things might have changed so don't quote me on that.
There is no security checkpoint, it's passport control, and they definitely let you pass if you have a LHR-bound BP.