It may also be important for maximising the amenity from various F lounges. For instance, a lengthy period in the SYD Flounge may be more attractive than, lets say the CX BKK or ICN F/J lounge. Likewise, the BA LHR T5 F (or Concorde) lounge may be a touch nicer than the FRA BA F lounge (if there is such a thing).
Very true and we still don't know what the OP wants.
Oh, and there is no BA F lounge in FRA.