There might still be a SAS lounge in BKK which you might use. This SAS lounge is definitely the best choice at BKK, in my view. When I was flying on Lufthansa out of BKK several times some months ago, I often went there and it was always crowded of other Lufthansa passengers who know that it's better than Thai's lounge or Lufthansa's lounge. But that's only my opinion.