Once again, although this is the first time I've seen it in the Prize crossword, there are 2 missing clues (12A and 19D) with the word "undefined" printed where the clues should be. (For a while this was a relatively regular occurrence in Qix's crossword on the back page of the main paper).
I don't know if readers who access the Herald online have the same problem. If not, I'd be grateful if someone could post the missing clues.