I'm sorry if there has already been a thread about this. I did a half-hearted search, but didn't really see what I was after.
For those of us that have Gs with world time, but no GMT/UTC city code, but the ability to set DST for a specific city code, could you just use London or Lisbon with DST turned off year-round for GMT? My incoming 7700 has the ability to turn DST on or off for specific cities without affecting the others. I assume then, that even when I turn on DST for my city code, London will still stay standard, thus effectively acting as GMT?