Thanks Andy, yes it was an analogue clock and white did not play their 35th move.
What happened was after black completed their 34th move, they noticed their flag had fallen and immediately owned up saying "och my flag has fallen". So there was no dispute, although nobody seemed to know what the actual rules were in this scenario.
Black later wondered if the flag fall may have irrelevant and if they could have just played on, which prompted me to find out.
No worries Jonathan. In that case it's definitely a loss for Black.
If white had made a move AND pressed his clock the game would have continued as far as I am aware. If White had made his 35th move and not pressed his clock yet, and Black's flag-fall was noticed at this point, I believe it's a loss for Black also - but maybe an arbiter can confirm all this?!
A move is “made” when the hand has quitted the piece being moved. In competition, a move is “completed” when the player’s clock has been stopped after the move is made.
If the player’s flag falls before the move is completed, the player loses on time if he has not completed the required number of moves. However, if the move has been “made” before flagfall, there is no loss on time if that move ends the game, eg by mate, creating a position which the opponent could not legally win, etc.
The flagfall can be pointed out until the opponent has played another move and pressed the clock. Thereafter the evidence would be destroyed.