The blue ones were only used for the viewers' competition IIRC

Yes, of course they were - that was just designed as a trick to catch people out! I simply asked which colour boxes were used, not whether it was for the game, viewer competition or otherwise! I can't see any occasion when they might use blue boxes for a game, unless combined with a light orange for summer specials or something...

Those blue boxes must have gathered a lot of dust by now...