Originally Posted by Johnosan
The BA website has a complete list of lounges that can be used by BA Exec Members. I imagine this would be the same for OW premium passengers.
That was a good idea and it is 90%+ accurate. Some of the BA lounges are contract lounges, thus not available to OW passengers -- for example Paris CDG. Unfortunately that list doesn't indicate this condition, but you will find out at the relevant airport. As the situation with Paris illustrates, some high-profile places have less lounge access than you would expect.