Ah, thanks both! I can see it now. My middle crosser was wrong (I had an A). I assumed that the answer might be the outer covering of the food item assiciated with the final word of the clue.
Interesting that, for 20d, the only anagram that Chambers gives is the solution that I originally had which gave me the incorrect crossing letter for 22a. All done now though.
In my opinion, yes. I think misdirections via punctuation, capitalisations, etc are all fair game for the setters. I'm pretty sure that 'nice' is regularly used to indicate French.