This is the update I have been procrastinating on, because the C grade was such a massive mess of unplayed games, of postponements and unannounced absences. Even Don Stracy, who constantly complains about other people not turning up, removed himself to Australia for 4-5 weeks of the duration of the competition.
In the end, it came down to the last game played, between Ryan Winter and Alexis Wevers. Ryan had won all the games he had played so far, although he was short of a few games, having been away himself, and having opponents not turn up on him. Ryan had to win against Alexis, but he did not manage this and so Alexis became the very deserving C grade champion.
I don't really know what can be done about some players' unreliability, but my solution to the C grade fiasco would be to combine this grade with the D grade in future, and make it one big Swiss tournament. At least if it was a Swiss it wouldn't matter if some people dropped out. You could have a separate grading prize to decide the D grade champion.