I was never charged, but others in my group were charged! Yes, it was GB Airways.
This however, was the Heathrow-Faro flight - which I am sure was either a Boeing 757 or Airbus A321. Something strange was that the flight was "operated by LOT" I am wondering whether this was a charter? I think I may have the boarding card somewhere...
Apologies, last time I checked I am sure BA were charging?