Travellin_man,
I think that the distinction is "Executive Club" versus "Club [class]" This crops up in a variety of BA lounges around Europe. When the gardener and I flew out of Zurich a couple of months ago, I wanted to spend some time in the Spruengli store, so I sent him off to the lounge ahead of me, bearing all the bags. He returned a few minutes later fuming because they wouldn't let him in - apparently his Club World ticket wasn't good enough: it was an Executive Club lounge, not a Club (Europe) lounge. So I duly trotted off with him and flashed my card, which allowed him entrance as my guest.
This makes sense most of the time in Zurich, as the club is tiny and fills up rapidly with all the commuting consultants, bankers etc, but we were flying on a Sunday morning, and were the only people using the lounge. I have to wonder whether the lounge attendant was simply too lazy to let the gardner in and clean up after him.
[The Spruengli lady, however, saw the steam coming out of his ears and offered him a free truffle, which did do something to sweeten his mood.]
I'll have to check the fine print on the oneworld info I have (from BA), but your experience seems to indicate that when there is an Executive Club lounge, that's the one to which you'll be admitted. In quieter airports the Exec Club club and the Club club are very often one and the same.