I had to reverse engineer a lot of the Calendar clues, but enjoyed the hunt. I'm in awe of setters who can compose a puzzle like this. Both IQ and The Listener "pushing the boundaries" this week.
I too had to do a lot of back engineering, but it helped once understanding how the calendar clues were entered. It's funny how the IQ and Listener often share the same theme in different manners - but I don't mind being spoilt.
Having finished ok on Saturday - just noticed - Old uproar about people of fashion and unusual American verse - I used wordplay without 'unusual' - presuming I have the correct answer what have I missed?