Could be that BA currently has it planned an 'old seat' 777-300ER but only selling it as 3-class. If that aircraft remains (highly unlikely this far out) BA would look to oversell Club World and use the First seats as extra Club seats (or FLUB seats FLUB class (travel in F but with J service on 4 class aircraft) - FlyerTalk Forums). Given all the changes to BA's fleet (early retirement of 747s and ongoing Club Suite installation) there will likely be some odd deployments over the next couple of years.