Yes, I hear they can be a bit funny if you try to use the FastTrack bridge from the multi-story if you haven't bought a parking ticket for there, even if you qualify otherwise, although any time I have used it there hasn't been anyone in the passageway to check.
There is a big list of all eligible users at the main entrance to security- I think
CWS posted the photo a while back.
Basically BA: Premier+2, Gold/OWE+1, Silver/OWS+1, Business UK, Club Europe, Club World, First.